Thousands of Filipino workers marched in annual May Day protests yesterday, denouncing the government and demanding higher wages, but renewed talk of coup plots appeared limited to rumour.

Security forces were on high alert in Manila as labour unions, pro-poor groups and opposition parties assembled in various parts of the capital, burning an effigy of President Gloria Macapagal Arroyo and chanting ?Oust Gloria?. Tensions often run high at the May Day event, this time fuelled by rising prices and pervasive corruption. There were some scuffles with baton-wielding police and a few arrests. ?This government is worse than a dictatorship. May 1 is for workers. Why is Arroyo preventing us from expressing our rights?? asked Daniel Adralin, head of a workers? group.

Some 6,000 supporters of the president, whose government faced down a brief mutiny by 300 soldiers in 2003, were brought by the busload to a rally in the capital?s Luneta Park. Analysts said there was little chance of unrest during the holiday weekend, but threats of instability cannot be entirely ignored after two popular revolts that chased out presidents and at least a dozen coup attempts in the last 20 years.

The government had warned of a plan by the opposition to take advantage of the May Day crowds, while a group of retired generals on Saturday called on Arroyo to quit and set out plans to overhaul the legislature and constitution. Layers of barbed wire and four shipping containers blocked the main road to the presidential palace, the scene of deadly clashes since the 1970s. Four armoured cars had been moved to the main military camp in Manila.

?We have not heard of any destabilisation plot,? Avelino Razon, police chief of Metro Manila, told reporters. ?This is a normal police operation but we will not tolerate violence.? Some analysts say the latest coup rumours seemed to be part of propaganda by both the opposition and the government.