PROTESTERS opposed to Myanmar's military coup blocked train services between Yangon and a southern city on Tuesday, hours after a U.N. envoy warned the army of "severe consequences" for any harsh response to the pro-democracy demonstrations.

Despite the deployment of armoured vehicles and soldiers in some major cities on the weekend, protesters have kept up their campaign to denounce the Feb. 1 takeover and demand the release of detained leader Aung San Suu Kyi and others.

As well as the demonstrations in towns and cities across the ethnically diverse country, a civil disobedience movement has brought strikes that are crippling many functions of government.

Protesters milled onto a sun-baked stretch of railway track waving placards in support of the disobedience movement, stopping the service between Yangon and the southern city of Mawlamyine, live images broadcast by media showed.

"Release our leaders immediately," and "People's power, give it back," the crowd chanted.

Crowds also gathered in two places in the main city of Yangon - at a traditional protest site near the main university campus and at the central bank, where protesters hoped to press staff to join the civil disobedience movement.

About 30 Buddhist monks protested against the coup with prayers.

The turnout at protests this week has been smaller than the hundreds of thousands who joined earlier demonstrations, but opposition to the army takeover that halted a decade of unsteady transition to democracy remains widespread.