At least two Buddhist monks were killed in Myanmar's main city on Wednesday when security forces moved in to disperse the biggest anti-junta demonstrations in 20 years, a monastery official said.

Earlier, troops fired shots over the heads of large crowds in Myanmar's main city, sending people scurrying for cover as a crackdown against the biggest anti-junta protests in 20 years intensified.

Two monks were killed and five wounded by bullets in Yangon, a hospital source said. Monks have been at the forefront of the demonstrations.

At least two witnesses saw the bloodied body of a monk being carried away after security forces stopped one procession as the city centre seethed with tens of thousands of people rebelling against decades of military rule. It was not clear whether he was dead or alive.

People have came out in force despite fears of a repeat of the bloody suppression of a 1988 uprising, when soldiers killed an estimated 3,000 people.

The protests began a month ago after sudden fuel price rises and have become a mass movement against military repression and economic hardship. - Reuters