A suspected bomb blast shook a luxury hotel in Myanmar's main city Yangon late on Monday, leaving one US guest slightly wounded, police said.
It was the latest in a series of mysterious bomb explosions in the former military-ruled country that have left two people dead and several wounded in recent days.
"An American woman who was staying inside the room was injured during the blast," according to a police official at the scene of the explosion at the Traders Hotel who did not want to be named.
"We assume that it was a bomb blast but we are still trying to find out more information," he told AFP.
The woman was taken to the Yangon General Hospital with wounds to her thigh and her hand, the official said.
He said the blast was believed to have happened in the guest's bathroom.
Her husband and two children, who were also staying in the hotel, were not injured.
Military officials and soldiers with sniffer dogs were seen at the hotel while shattered glass lay on the road outside.
The hotel, part of the Shangri-La group, is located in the heart of Myanmar's commercial hub. It is popular with foreign tourists and visiting business people.
The incident came amid heightened security concerns in the country following a series of bomb blasts by unknown perpetrators.
A man and a woman were killed and another person was injured in an explosion Friday at a guesthouse in the town of Taunggu about 65 kilometres (40 miles) from the capital Naypyidaw, police said.
Two other devices exploded in Yangon on Sunday -- one at a bus stop and another under a truck which wounded two teenagers, according to the authorities.
Two more makeshift devices were found in the cities of Yangon and Mandalay on Monday.
"We cannot say who is responsible for these acts," said Police Lieutenant General Min Aung of the Myanmar Police Force's intelligence and security department.
"We're still investigating. The system they used is the same in all the cases. We think an organisation or a person planted them all," he told AFP by telephone from Naypyidaw, speaking before the blast at the Traders Hotel.
Bomb blasts were relatively common under the former junta, which usually blamed the explosions on armed exile groups or ethnic rebels.
But such explosions are less common under a new quasi-civilian government which took power in 2011, promising political reforms and efforts to end long-running ethnic insurgencies.
In a message posted on its official Facebook page, the Yangon police appealed to people to be vigilant for any suspicious objects at railway stations, bus stops and other public places.
"We also urge people to cooperate to find those causing unrest and casualties with explosions," it said.
President Thein Sein's reformist government has reached tentative peace deals with the major ethnic minority rebel groups in the country, which has been wracked by civil wars since independence from Britain in 1948.
But the nation has been hit by several outbreaks of Buddhist-Muslim religious violence since June 2012 that have left about 250 people dead and more than 140,000 homeless, mostly Muslims.