Bangkok  - A grenade attack early Sunday on protestors who have occupied Government House, the seat of the administration, wounded 46 people, with at least two listed in critical condition, media reports said.

The explosion occurred shortly after midnight as members of the People's Alliance for Democracy (PAD) gathered around a stage to listen to speeches, The Nation online news service reported.

The M79 grenade exploded just 200 metres away from the PAD's main stage inside Government House. Similar attacks on demonstrators in recent weeks have killed at least one person and left dozens injured.

The anti-government PAD has occupied Government House since August 26 and now also holds Bangkok's two airports hostage to its demand that the government steps down.

The closure of the airports, which has completely cut off the capital to air traffic since Thursday, has caused millions of dollars in daily damage to the economy and billions of looming losses in the future to the tourism and export industries.

More than 100,000 tourists have been stranded in Bangkok as a result of the closures.

Although Thai Prime Minister Somchai Wongsawat put both airports under emergency decree on Thursday and ordered the police to clear the facilities of demonstrators, authorities have failed to act.

With Thailand's Constitution Court expected to rule Tuesday on the dissolution of the People Power party, which leads the current government, the police are hesitant to take responsibility for an assault on the airports that would lead to bloodshed, observers said.

If the court rules to dissolve the People Power party for condoning election fraud in the December 23, 2007 polls, Somchai will lose his post and be banned from politics for five years. (dpa)