Tens of thousands of anti-government demonstrators have taken to the streets of Thailand's capital to protest what they say is ousted Prime Minister Thaksin Shinawatra's influence on the current government.

Rally leader and former opposition lawmaker Suthep Thaugsuban called Sunday for a 1 million-strong overnight rally against Thaksin, whose younger sister Yingluck is the current prime minister.

Special peace-keeping command spokesman police Maj. Gen. Piya Uthayo said intelligence reports indicated the protesters would move to surround key Bangkok locations, including the prime minister's office and Parliament.

A new round of street demonstrations was triggered last month by a government-backed bill that could have granted amnesty to the exiled Thaksin, who was ousted in a 2006 coup.

A smaller group of pro-government Red Shirt protesters gathered Sunday to support Yingluck's administration.