Police in Myanmar confirmed on Tuesday that a blast at a luxury hotel in Yangon that wounded a US guest was caused by a bomb.
"It was a time bomb. It was attached to a clock," said a police official who visited the scene of the explosion, which happened late on Monday at the Traders Hotel.
Officials said they had detained a man who previously stayed in the hotel room where the blast occurred for questioning.
"The man who stayed there before the American family at the Traders Hotel was arrested as a suspect," a second police official said.
He said the man was arrested early Tuesday in the southeastern state of Mon.
"But it's still early to say he planted the bomb without further investigation," the official added.
Two other suspects have been detained for questioning in connection with an earlier series of unexplained explosions, he said.
A man and a woman were killed and another person 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 authorities.
Two more makeshift devices were found in the cities of Yangon and Mandalay on Monday.
Authorities said the recent incidents could be aimed at derailing the country's pro-democratic reforms as it prepares to host a major regional sporting event in December and take the chair of the Association of Southeast Asian Nations (ASEAN) next year.