Singapore's Prime Minister Lee Hsien Loong has written to Indonesia's President Joko Widodo, expressing his "deepest condolences" to the families of those on board the Trigana Air jet that crashed in the eastern province of Papua on Sunday.

Mr Lee said in his letter, released on Monday by Singapore's Ministry for Foreign Affairs, that he was "saddened" to hear of the crash of flight IL267, which had 54 people on board.

He also conveyed his sympathies on behalf of the Singapore Government.