COLOMBO (Reuters) -- Tens of thousands of supporters mobbed Sri Lankan Prime Minister Ranil Wickremesinghe as he arrived home on Friday for a showdown with the island's president that threatens a peace process with Tamil rebels.

Fresh from receiving a seal of approval for his peace bid from the United States, Wickremesinghe was garlanded with flowers and bowed to a group of Buddhist monks after he stepped off the plane.

"Parliament must reassemble. It is the only body with a mandate for negotiations," Wickremesinghe said on his arrival, three days after President Chandrika Kumaratunga suspended parliament and sparked a crisis that threatens a 20-month ceasefire with Tamil Tiger rebels.

Kumaratunga accused the government of giving away too much to the Liberation Tigers of Tamil Eelam (LTTE), one of the world's most ferocious guerrilla groups, and said she was acting in the country's interests.

Political observers said the standoff over the peace process could end in a general election, the third in four years.

"My priority is to meet the donor nations, including Norway and India," Wickremesinghe said as supporters waved banners and chanted his name outside the airport.

Norway brokered the truce with the Tigers and neighboring India has already voiced concern the political stalemate could threaten the peace effort.

The rebels from the minority Tamil community said on Friday they would be patient.