Colombo: United National Party leader Ranil Wickremesinghe was sworn in as the Prime Minister of Sri Lanka on Sunday, ending a 51-day power tussle in the island nation that had crippled the government.

Wickremesinghe was administered the oath of office by President Maithripala Sirisena at a simple ceremony held at the Presidential Secretariat here.

His appointment comes hours after former strongman Mahinda Rajapaksa, who was appointed Prime Minister by President Maithripala Sirisena, resigned Saturday, paving way for the return of Wickremesinghe as premier.

President Sirisena had sacked Wickremesinghe on October 26, in a controversial move which plunged the island nation into an unprecedented constitutional crisis.

Sirisena agreed to reinstate Minister Wickremesinghe in the post after a discussion with him over the phone on Friday.