An explosion that struck one of the most prestigious hotels in Myanmar's main city was caused by a small, homemade time bomb, police said Tuesday.
Officer Myint Htwe said three suspects have been detained in relation to the blast, which went off just before midnight Monday at the Traders Hotel in the heart of Yangon, wounding a 43-year-old American woman as it ripped apart her 9th floor room.
Her husband and two young children were unharmed.
It was one in a series of unexplained explosions to hit the country in recent days, resulting in several injuries, the most recent occurring in Mandalay region before dawn Tuesday.
Small bombings occurred frequently when Myanmar was under 50 years of brutal military rule, most often blamed on armed exiled groups or ethnic rebels. But they have become rare since the nominally civilian government of President Thein Sein, a former army general, took office two years ago and started implementing a series of major political and economic reforms.
His spokesman, Ye Htut, told Radio Free Asia the incidents may be aimed at smearing the country's image.
"I think that the explosions may have been timed to coincide with Myanmar becoming the chair of ASEAN," he told RFA Myanmar's service, referring to the regional grouping.
Myanmar is also preparing to host the Southeast Asian Games, the region's largest sports event, after a 44-year hiatus, he noted.
"Someone or some organization" wants to "make the international community misunderstand the situation of stability and peace in Myanmar," he said.
The explosion at the 22-story Trader's Hotel, located in the heart of the country's commercial capital, 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 her bathroom, scattering towels, toiletries and a red purse across the entrance way floor. A chair was overturned and part of the wooden wardrobe lifted off its hinges and lying on the ground.
The American woman was slightly injured - witnesses saw blood on her arm and below her waist as she was escorted through the lobby by her husband - and taken to a Yangon hospital.
"Our consular officers in Rangoon (Yangon) have visited the U.S. citizen and are providing appropriate consular assistance," said Sarah Hutchison, the U.S. Embassy press officer, refusing further comment due to privacy considerations.
A dozen police and heavily armed soldiers with a sniffer dog entered the glitzy hotel soon after the explosion. 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."
The country has undergone rapid change since 2011, but many activists and rights groups have complained that country is still far from free, and dissent is frequently stifled despite reforms that have liberalized the economy and the political sphere.
Censorship has been eased and hundreds of political prisoners released.
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.
Unidentified assailants have planted several homemade bombs in and around Yangon in recent days, reportedly killing two people and injuring three others.
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.
The explosions Tuesday occurred at 3 a.m. and 5 a.m. in Sagain, in Mandalay region. No further details were available.
Police called on the public to be vigilant and report any suspicious packages found at bus or train stations, or at the seaport.