UPDATE 1-Sri Lanka's prime minister to resign from office this week -spokesman

Sri Lankan Prime Minister Ranil Wickremesinghe will resign from office this week, said a spokesman for his office on Wednesday, a move that comes just days after his party's candidate lost a presidential election over the weekend. "The resignation letter will be sent (to the President) by tomorrow," Sudharshana Gunawardena, a spokesman for the Prime Minister told Reuters on Wednesday.

Sources had earlier told Reuters that Wickremesinghe's exit was imminent and local media separately reported that new Sri Lankan President Gotabaya Rajapaksa would soon name an interim cabinet to govern the island until the next election, expected around April. Former war-time defence minister Rajapaksa of the Sri Lanka Podujana Peramuna (SLPP) won the presidency by a sizable margin in Saturday's vote, defeating former housing minister Sajith Premadasa, the candidate of Wickremesinghe's United National Party (UNP)-led coalition.