MANILA, Philippines - The Philippine president has received rare praises from key critics for invoking before the United Nations a 2016 arbitration ruling that invalidated China's vast territorial claims in the South China Sea.

His surprise move will likely pique Beijing.

President Rodrigo Duterte made one of his strongest defences of the landmark ruling in his first address before the annual U.N. General Assembly.

China has long refused to bring the issue to any international arena and Duterte has nurtured close ties with Beijing.

China refused to take part in the arbitration and has dismissed the ruling as a sham.

Beijing prefers direct negotiations with each of its rival claimants in the disputed waters and has vehemently refused to have the case internationalized.