About 5,000 demonstrators opposed to Thailand's military-installed government clashed with police in Bangkok Sunday and demanded the resignation of a top adviser to the king.

The protesters, mainly supporters of Thailand's former prime minister, staged a rally outside the home of Prem Tinsulanonda, chief adviser to King Bhumibol Adulyadej, accusing him of masterminding the coup last September that ousted government chief Thaksin Shinawatra.

When police tried to disperse the crowd, the protesters hurled rocks, bottles and other objects at them.

Hospital sources say at least 30 people, including police officers, were treated for various injuries.

Organizers of the protest accused authorities of overreacting, saying the authorities did not try to negotiate with protest leaders.

Thai military leaders seized power when Mr. Thaksin was out of the country. They accused him of corruption and abuse of power.

An interim government appointed by Thailand's military leaders has issued a new constitution intended to guide the country toward elections by the end of this year. A referendum on the charter will be the public's first opportunity to cast a vote on the past year's upheaval.

Most of those involved in Sunday's protest were members of the former ruling political party Thai Rak Thai, which has been disbanded. Thaksin, who was the party leader, has been barred from taking part in future elections; he has said he will remain outside Thailand until democracy returns.

Some information for this report was provided by AP and Reuters.