ISLAMABAD — Soldiers sent to halt a Taliban advance toward the Pakistani capital fought their way over a mountain pass Thursday, killed at least 14 militants and narrowly escaped a wave of suicide car bombers, the army said.
As troops pursued an offensive praised by the United States, a burst of shootings in a southern city left dozens dead and added the specter of ethnic conflict to the Islamist violence gnawing at the nuclear-armed country's stability.
President Asif Ali Zardari urged ordinary Pakistanis to support the operation in the Buner region so the Islamic nation would remain under "a moderate, modern and democratic state."
But there was anger and skepticism among hundreds of residents fleeing Buner on Thursday to join more than half a million others displaced by fighting that has flared across the northwest over the past year.
"Both sides bring us trouble: The Taliban is shelling, the army is shelling," said Taj Mohammed, a 43-year-old farmer driving a pickup truck carrying more than a dozen relatives. "Why are they putting our women and children in danger? We want peace, whether it comes through the government or the Taliban."
Security forces backed by artillery and warplanes began pushing into Buner, a district just 60 miles (100 kilometers) from Islamabad, on Tuesday after Taliban militants from the neighboring Swat Valley infiltrated the area under cover of a peace pact.
On Thursday, troops ousted militants from the Ambela Pass leading over the mountains into Buner and were inching toward the north, army spokesman Maj. Gen. Athar Abbas said.
Soldiers opened fire on four suspected suicide car bombers who drove toward them near the pass, Abbas said. Two vehicles exploded while the other two managed to drive away. No troops were hurt, he said.
Troops also destroyed four militant vehicles in Dir, a district to the west, Abbas said. In all, at least 14 militants were killed and one soldier was wounded in the previous 24 hours, he said.
Abbas also said militants, who have kidnapped dozens of lightly armed police and paramilitary troops, burned a police station farther north and sealed off the town of Sultanwas.
"The people of Sultanwas are in great distress," Abbas said at a news conference. "Nobody is being allowed to move out of Sultanwas."
He also said militants killed a police officer and threw his body into a river in Swat, but said the peace deal centered on the valley remained "intact."
A spokesman for the Taliban in Swat insisted they were sticking to the peace process. The militants in Buner were all local Taliban, Muslim Khan said.
"They are our friends and they have not suffered any big losses so far," Khan said.
Security forces barred some reporters from entering Buner and telephone connections were cut, making it hard to gain firsthand accounts of the fighting.
U.S. leaders sharply criticized Zardari's decision to sign a law imposing Islamic law in Swat and the surrounding Malakand region in an attempt to halt two years of bloody and inconclusive fighting.
Defenders of the pact say the Islamic law concession will isolate hard-liners bent on destabilizing the country and bolster thin public support for any later crackdown.
Officials said Thursday the Islamic courts will be up and running within days, despite the growing violence.
The "time has come for the entire nation to give pause to their political differences and rise to the occasion and give full support to our security forces in this critical hour," Zardari said in a statement. "This is the only way to demonstrate our will to keep Pakistan as a moderate, modern and democratic state where the rights of all citizens are protected."
Pakistan's stability is complicated by deep ethnic and sectarian tensions that are likely to grow as a result of a marked slowdown in economic growth.
Competition for jobs and political power is sharpest in Karachi, a teeming southern port with a history of ethnic violence where shooting broke out late Wednesday.
Much of the tension has been between the Pashtun population, who dominate the violence-plagued northwest, and Urdu-speaking Mohajirs descended from migrants from India.
The main Mohajir political party that runs the city, the Muttahida Quami Movement, has been outspoken against the Pashtun-dominated Taliban and has warned the militants represent a growing threat in Karachi, Pakistan's 16-million strong commercial hub.
The city was largely crippled Wednesday after two MQM activists were gunned down by unknown assailants, sparking street violence that had abated by dawn.
Paramilitary rangers patrolled the city's trouble spots Thursday, as doctors and police said the death toll reached 34, with about 50 others wounded.
The Obama administration, determined to stop militants from using Pakistan as a base for attacks in Afghanistan, is asking Congress for more money to aid the Pakistani army.
In a news conference Wednesday marking his first 100 days in office, Obama said he was "gravely concerned" about Pakistan's stability, saying it was struggling to deliver even basic services such as health care and education.
Obama expressed confidence that Pakistan's army would continue to keep its nuclear arsenal secure _ though left the door open for U.S. action if necessary.
Associated Press writers Ashraf Khan in Karachi and Lara Jakes in Washington contributed to this report.