BANGKOK: Opposition members in Thailand's Parliament called Monday for the resignation of the foreign minister after police filed charges against him for alleged involvement in demonstrations that climaxed with the seizure of Bangkok's airports last year.

Foreign Minister Kasit Piromya and 35 other leaders of the "Yellow Shirt" movement face criminal charges including illegal assembly, attempts to stir unrest, and breaches of aviation law and terrorism for the eight-day siege of Bangkok's two airports in November and December.

They were summoned to report to police on July 16, said Police Lt. Gen. Wuthi Puavej.

The charges brought a controversy surrounding Kasit's appointment as foreign minister to the forefront.

"The charges are very serious. How could he represent our country as a foreign minister? He has no credibility left," said Prompong Nopparit, spokesman of the opposition Phuea Thai Party.

Kasit spoke at several rallies by the protesters, who sought to topple the previous government allied with former Prime Minister Thaksin Shinawatra. They accused Thaksin, who was toppled in a military coup in 2006, of massive corruption and abuse of power.

The protesters occupied the prime minister's office compound for three months and shut down Bangkok's airports. Kasit later hailed the blockade — which stranded more than 250,000 travelers — as an "innovation in public protests."

On Sunday, Prime Minister Abhisit Vejjajiva said Kasit will remain in office while he fights the charges.

Jatuporn Phrompan, a member of Parliament from Phuea Thai Party, said the lack of immediate response from the government "sends a signal that they do not take these charges against the Yellow Shirts seriously."

Kasit declined to comment on the charges after returning to Bangkok Monday from Qatar.

Thailand was destabilized by months of protests by both supporters and opponents of Thaksin.

Abhisit's government took control in December after a court ruled that the previous pro-Thaksin ruling party was guilty of election fraud. The court ruling prompted protesters to abandon the siege of the airports.

Abhist's six-month-old government has since faced street protests by Thaksin's supporters or the "Red Shirts" this year. Rioting in April left two dead and more than 120 injured.