TRIPOLI, Libya (AP) -- Libyan rebels raced into Tripoli Sunday and met little resistance as Moammar Gadhafi's defenders melted away and his 42-year rule rapidly crumbled. The euphoric fighters celebrated with residents of the capital in Green Square, the symbolic heart of the fading regime.
Gadhafi's whereabouts were unknown, though state TV broadcast his bitter pleas for Libyans to defend his regime. Opposition fighters captured his son and one-time heir apparent, Seif al-Islam, who along with his father faces charges of crimes against humanity at the International Criminal Court in the Netherlands. Another son was in contact with rebels about surrendering, the opposition said.
"It's over, frizz-head," chanted hundreds of jubilant men and women massed in Green Square, using a mocking nickname of the curly-haired Gadhafi. The revelers fired shots in the air, clapped and waved the rebels' tricolor flag. Some set fire to the green flag of Gadhafi's regime and shot holes in a poster with the leader's image.
By the early hours of Monday, rebels controlled large parts of the capital. They set up checkpoints alongside residents - many of them secretly armed by rebel smugglers in recent weeks. But pockets of pro-Gadhafi fighters remained: In one area, Associated Press reporters with the rebels were stopped and told to take a different route because of regime snipers nearby.
"We were waiting for the signal and it happened," said Nour Eddin Shatouni, a 50-year-old engineer who was among the residents who flowed out of their homes to join the celebrations. "All mosques chanted 'God is great' all at once. We smelled a good scent, it is the smell of victory. We know it is the time."
The seizure of Green Square held profound symbolic value and marked a stunning turn in the tide of the 6-month-old Libyan civil war. The regime has held pro-Gadhafi rallies there nearly every night since the revolt began in February, and Gadhafi delivered speeches to his loyalists from the historic Red Fort that overlooks the square.
The sweep into the capital came after the rebel fighters advanced 20 miles from the west in a matter of hours. They took town after town and overwhelmed a major military base meant to defend Tripoli, 16 miles from the city. All the way, they met little resistance and residents poured out on the streets to welcome them.
In a series of angry and defiant audio messages broadcast on state television, Gadhafi called on his supporters to march in the streets of the capital and "purify it" of "the rats." He was not shown in the messages.
His defiance raised the possibility of a last-ditch fight over the capital, home to 2 million people. Government spokesman Moussa Ibrahim claimed the regime has "thousands and thousands of fighters" and vowed: "We will fight. We have whole cities on our sides. They are coming en masse to protect Tripoli to join the fight."
But it appeared that Gadhafi's military was abandoning him quickly.
The rebels' way into Tripoli was opened when the military unit in charge of protecting Gadhafi and the capital surrendered, ordering his troops to drop their weapons, the rebel information minister Mahmoud Shammam said.
In a sign of the coordination among rebels, as the main force moved into the city from the west, a second force of 200 opposition fighters from the city of Misrata further east landed by boat in the capital. They brought weapons and ammunition for Tripoli residents who join the rebellion, said Munir Ramzi of the rebels' military council in Misrata.
NATO Secretary-General Anders Fogh Rasmussen said Gadhafi's regime was "clearly crumbling" and that the time to create a new democratic Libya has arrived.
The sooner Gadhafi "realizes that he cannot win the battle against his own people, the better," he said in a statement, adding that NATO will continue to strike his troops if they make "any threatening moves toward the Libyan people."
In a statement early Monday, President Barack Obama said the way to prevent more bloodshed was for Gadhafi "to relinquish power once and for all." Obama said the rebel leaders must pursue a peaceful transition to democracy.
It was a stunning reversal for Gadhafi, who earlier this month had seemed to have a firm grip on his stronghold in the western part of Libya, despite months of NATO airstrikes on his military. Rebels had been unable to make any advances for weeks, bogged down on the main fronts with regime troops in the east and center of the country.
Gadhafi is the Arab world's longest-ruling, most erratic, most grimly fascinating leader - presiding for 42 years over this North African desert republic with vast oil reserves and just 6 million people. For years, he was an international pariah blamed for the 1988 bombing of a Pan Am jumbo jet over Lockerbie, Scotland, that killed 270 people. After years of denial, Gadhafi's Libya acknowledged responsibility, agreed to pay up to $10 million to relatives of each victim, and declared he would dismantle all weapons of mass destruction.
That eased him back into the international community.
But on February 22, days after the uprising against him began, Gadhafi gave a televised speech amid violent social unrest against his autocratic rule. In the speech, he vowed to hunt down protesters "inch by inch, room by room, home by home, alleyway by alleyway." The speech caused a furor that fueled the armed rebellion against him and it has been since mocked in songs and spoofs across the Arab world.
As the rebel force advanced on Tripoli, taking town after town, thousands of jubilant civilians rushed out of their homes to cheer the long convoys of pickup trucks packed with fighters shooting in the air. One man grabbed a rebel flag that had been draped over the hood of a slow-moving car and kissed it, overcome with emotion.
Some of the fighters were hoarse, shouting: "We are coming for you, frizz-head." In villages, mosque loudspeakers blared "Allahu Akbar," or "God is great."
"We are going to sacrifice our lives for freedom," said Nabil al-Ghowail, a 30-year-old dentist holding a rifle in the streets of Janzour, a suburb just six miles west of Tripoli. Heavy gunfire erupted nearby.
As rebels moved in Tripoli, thousands celebrated in the streets of Benghazi, the rebels' de facto capital hundreds of miles to the east. Firing guns into the air and shooting fireworks, they cheered and waved the rebel tricolor flags, dancing and singing in the city's main square.
Rebel chief Mustafa Abdel-Jalil in Benghazi confirmed to the AP that the rebels arrested Gadhafi's son Seif al-Islam but refused to give the details of the capture.
"We have captured Seif al-Islam and he is in safe hands," he said.
In the Netherlands, the prosecutor at the International Criminal Court, Luis Moreno-Ocampo, said his office would talk to the rebels on Monday about Seif al-Islam's transfer for trial. "It is time for justice, not revenge," Moreno-Ocampo told the AP.
Seif al-Islam, his father and Libya's intelligence chief were indicted earlier this year for allegedly ordering, planning and participating in illegal attacks on civilians in the early days of the violent crackdown on anti-regime protesters.
Another son, Mohammed, was in contact with the rebels and was asking for guarantees for his safety, said rebel spokesman Sadiq al-Kibir. Mohammed, who is in charge of Libyan telecommunications, appeared on the Arabic satellite channel Al-Jazeera, saying his house was surrounded by armed rebels.
"They have guaranteed my safety. I have always wanted good for all Libyans and was always on the side of God," he said. Close to the end of the interview, there was the sound of heavy gunfire and Mohammed said rebels had entered his house before the phone line cut off.
A rebel spokesman based in London said Gadhafi's prime minister, Al-Baghdadi Al-Mahmoudi, was in a Tunisian hotel, indicating he had joined a growing list of defecting officials.
The day's first breakthrough came when hundreds of rebels fought their way into a major symbol of the Gadhafi regime - the base of the elite 32nd Brigade commanded by Gadhafi's son, Khamis. Fighters said they met with little resistance. They were 16 miles from the big prize, Tripoli.
Hundreds of rebels cheered wildly and danced as they took over the compound filled with eucalyptus trees, raising their tricolor from the front gate and tearing down a large billboard of Gadhafi. From a huge warehouse, they loaded their trucks with hundreds of crates of rockets, artillery shells and large-caliber ammunition.
One group started up a tank, drove it out of the gate, crushing the median of the main highway and driving off toward Tripoli.
"This is the wealth of the Libyan people that he was using against us," said Ahmed al-Ajdal, 27, pointing to his haul. "Now we will use it against him and any other dictator who goes against the Libyan people."
At the base, the rebels also freed more than 300 prisoners from a regime lockup, most of them arrested during the heavy crackdown on the uprising in towns west of Tripoli. The fighters and the prisoners - many looking weak and dazed and showing scars and bruises from beatings - embraced and wept with joy.
"We were sitting in our cells when all of a sudden we heard lots of gunfire and people yelling 'God is great.' We didn't know what was happening, and then we saw rebels running in and saying 'We're on your side.' And they let us out," said 23-year-old Majid al-Hodeiri. He said he was captured four months ago by Gadhafi's forces crushing the uprising in his home city of Zawiya. He said he was beaten and tortured while under detention.
From the military base, the convoy sped toward the capital.
Mahmoud al-Ghwei, 20 and unarmed, said he had just came along with a friend for the ride .
"It's a great feeling. For all these years, we wanted freedom and Gadhafi kept it from us. Now we're going to get rid of Gadhafi and get our freedom," he said.
The uprising against Gadhafi broke out in mid-February, and anti-regime protests quickly spread. A brutal regime crackdown quickly transformed the protests into an armed rebellion. Rebels seized Libya's east, setting up an internationally recognized transitional government there, and two pockets in the west, the port city of Misrata and the Nafusa mountain range.
Gadhafi clung to the remaining territory, and for months neither side has been able to break the other.
In early August, however, rebels launched an offensive from the Nafusa mountains, intending to open a new, western front to break the deadlock. They fought their way down to the Mediterranean coastal plain, backed by NATO airstrikes, and captured the strategic city of Zawiya.
On Saturday, they consolidated control of Zawiya, then launched their furious rush on the capital.
At the same time, rebel "sleeper cells" inside Tripoli rose up and clashed with Gadhafi loyalists. Rebel fighters who spoke to relatives in Tripoli by phone said hundreds rushed into the streets in anti-regime protests in several neighborhoods on Sunday.
"We received weapons by sea from Benghazi. They sent us weapons in boats," said Ibrahim Turki, a rebel in the Tripoli neighborhood of Tajoura, which saw heavy fighting the past two days. "Without their weapons, we would not have been able to stand in the face of the mighty power of Gadhafi forces."
Hadeel Al-Shalchi in Cairo contributed to this report.