Yangon bomb wounds 4 as protest anniversary looms

YANGON (Reuters) - A bomb exploded outside City Hall in Myanmar's main city on Thursday, wounding four people the day before the anniversary of a bloody military crackdown on anti-government protests.

"It seems to have been a small bomb but we are still carrying out investigations," a policeman, who did not want to be identified, told Reuters at the scene of the blast near a busy bus terminal in the heart of Yangon.

Anybody from underground pro-democracy groups to ethnic minority guerrillas to the military government itself could be behind the blast, which left few signs of damage, according to a diplomat who arrived shortly afterwards.

"It could have been anyone on any side with any number of objectives," the diplomat said. "There wasn't some great big hole in the ground, but people were injured and it was right in the middle of downtown."

Small bombs are relatively common in Myanmar. The junta routinely blames them on dissidents in exile or the jungle militias that have been fighting the ethnic Burmese majority since shortly after independence from Britain in 1948.

Three women and a man were wounded, but the police officer said they were not thought to be seriously hurt.

Armed police and soldiers immediately sealed off the area, a focal point of the massive marches by Buddhist monks a year ago against army rule stretching back to 1962.

At least 31 people were killed in the ensuing crackdown, which drew worldwide condemnation when it was launched on September 26, 2007.

With the anniversary looming, security in the former capital has been unusually tight, with armed police and troops patrolling the streets and setting up vehicle checkpoints.

The area around City Hall and the Sule Pagoda, where the monk's marches ended, has been under particularly tight watch.

At least 3,000 people were arrested in the crackdown and its aftermath. Human rights groups say as many as 700 people remain behind bars, although the junta says all but a few dozen have been released.

Earlier this month, female activist Nilar Thein, a student leader in a brutally crushed democracy uprising in 1988 and an organiser of the 2007 protests, was detained after a year on the run.

She went into hiding, abandoning her four-month-old daughter, when her husband was arrested in August for helping stage the small fuel and food price protests that snowballed into the monk-led demonstrations a month later.

The detention of the still-influential 1988 uprising leaders -- the so-called "88 Generation Students" -- makes any demonstration to mark the anniversary inside Myanmar extremely unlikely. Events are planned for outside the country.

News websites run by exiled dissidents, most of them in neighbouring Thailand and India, have come under cyber-attack in the past week in what they say is an attempt by the generals to prevent coverage of the demonstrations.

(Writing by Ed Cropley; Editing by Alan Raybould)