Thai Prime Minister Abhisit Vejjajiva was accused on Tuesday of violating human rights during crackdowns on protesters as lawmakers kicked off a no-confidence debate against his government.

Two Thai Air Force F-16 jet fighters crashed on Monday in Northeastern Thailand during a joint exercise with the US military but neither pilot was injured, an official said.

Battle between Myanmar government soldiers and ethnic karen forces have continued along the Thai-Myanmar border near Mae Sot District of Thailand's northwestern Tak Province.

The bodies of more than 100 human foetuses, apparently from an illegal abortion clinic, were discovered inside a Buddhist temple in central Bangkok, the Thai police said on Monday.

Thai authorities have arrested 61 Tamil migrants from Sri Lanka, the police said on Saturday, in the second such crackdown in recent weeks.

The Thai government said on Tuesday it was extending a state of emergency in Bangkok and three surrounding provinces for three more months, in the wake of deadly street protests in April and May.

Thailand on Friday revoked a state of emergency in three northeastern provinces but not in Bangkok, where there have been a series of minor blasts in recent weeks, a government spokesman said.

Thai immigration police arrested a Japanese man on suspicion he fabricated an official document declaring him dead to claim $5.81 million from an insurance firm, the police has said.

Several hundred Red Shirt protesters defied a state of emergency in the Thai capital to stage a symbolic protest, with hundreds of people sprawling on the ground and chanting, “People died here!”

A grenade exploded near a Bangkok shopping mall on early Friday, injuring one person and rattling the Thai capital less than a week after a similar blast left a bystander dead and several more hospitalised.