It was the second deadline the opposition has given Thaksin Shinawatra, who has been battling weeks of mass demonstrations calling for him to resign since his family pocketed almost two billion dollars in a tax-free stock sale.

"There is nothing that worries me about the current situation," Thaksin told reporters as he entered his offices -- which have been surrounded since last week by demonstrators -- for the first time in 10 days.

"Everything is fine," he said, adding that he did not expect protests to turn violent after the announced deadline expired.

"The dateline expires at 10:00 pm (1500 GMT) and we will announce our next step on that stage. I cannot disclose what it will be now," said Suriyasai Katasila, spokesman for the main anti-Thaksin alliance.

He said the movement would take a "decisive measure."

Media reports said the People's Alliance for Democracy was mulling a march on Thaksin's Bangkok residence.

Another option would be to ask a "third power" -- thought by many to be King Bhumibol Adulyadej -- to intervene and end the political crisis, the Nation newspaper said.

Tens of thousands of protesters have been gathering every night for weeks in downtown Bangkok to oppose Thaksin, who called early elections for next month in hopes of drawing a line under the political crisis.

Thaksin remains widely popular in the country's rural areas and analysts expect he would win the April 2 vote by a comfortable margin.

But in the capital, nightly protests have given voice to anger over his family's sale of the Thai telecom giant Shin Corp to investors from Singapore.

The deal earned Thaksin's family 1.9 billion dollars and used legal loopholes to avoid paying taxes.