YANGON, Myanmar -- YANGON, Myanmar (AP) — An explosion struck one of the most prestigious hotels in Myanmar's main city just before midnight Monday, ripping apart a guest's room and wounding one American — the latest in a series of unexplained blasts to hit the Southeast Asian country.
It was not immediately clear what caused the explosion in the 22-story Trader's Hotel. But the incident came after unidentified assailants planted three homemade bombs in and around Yangon in recent days, reportedly killing two people and injuring three others.
The blast late Monday blew out a window in the guest's 9th floor room, shooting shards of thick glass more than 30 meters (yards) into the street, but there were no other visible signs of damage to the exterior of the building.
The device apparently went off in the guest's bathroom, towels, toiletries and a red purse scattered across the entrance way floor. A chair was overturned and part of the wooden wardrobe lifted off its hinges and lying on the ground.
A 43-year-old American woman was slightly injured and taken to a Yangon hospital, according to a police officer at the scene who declined to be named because he was unauthorized to speak about the incident. Her husband and their two children, aged 5 and 7, were unhurt.
An American Embassy official, police and hotel staff declined to say whether the explosion was caused by a bomb.
A dozen police and heavily armed soldiers with a sniffer dog entered the glitzy hotel, located in the heart of Yangon. Later, many of them crowded into the destroyed room, blocked off with yellow security tape, to inspect the damage.
Others carrying assault rifles and wearing bullet proof vests strolled through the main lobby.
Traders' general manager Phillip Couvaras said in a statement that the hotel, part of the Shangri-La group, was working with authorities to investigate what happened.
But "because this is an active police investigation we cannot comment further at this time," he said. "The safety of our guests and staff are our highest priority and we are obviously monitoring the situation."
Small explosions occurred frequently when Myanmar was under 50 years of military rule, most often blamed on anti-government student activists or armed ethnic insurgent groups. But such incidents have become rare in recent years.
The country has undergone rapid change since 2011, when the former army junta ceded power to a quasi-civilian government led by retired military officers. Since then, President Thein Sein has embarked upon a series of major reforms, liberalizing the economy and the political sphere, easing censorship and freeing political prisoners.
But many activists and rights groups have complained that country is still far from free, and dissent is frequently stifled. Thein Sein's government has also struggled both to end a civil war with ethnic Kachin rebels in the north, and curb a rising wave of anti-Muslim violence that has killed hundreds of minority Muslims and displaced nearly 150,000 more in the predominantly Buddhist country since last year.
No one claimed responsibility for the recent blasts, which came as the country prepares to host the Southeast Asian Games in December. Police earlier speculated forces might try to use violence to discredit the government before the showcase event.
The first bomb reportedly went off Friday at a guesthouse in Taungoo, a town 200 kilometers (125 miles) from Yangon, according to the independent media outlet, the Democratic Voice of Burma. It said two people were killed, but those casualties could not immediately be confirmed.
On Sunday, two other homemade bombs went off in Yangon. One of the bombs, attached to the bottom of a truck parked outside a market on Yangon's eastern side, wounded three civilians, according to a statement posted on Myanmar's police Facebook page.
Another homemade bomb exploded one at a bus stop in the west of the city, but no casualties were reported in that blast, police said.
Police called on the public to be vigilant and report any suspicious packages found at bus or train stations, or at the seaport.
Associated Press writers Aye Aye Win, Esther Htusan and Todd Pitman contributed to this report.