BANDAR SERI BEGAWAN, Brunei: China’s territorial disputes with its neighbors and choking smog in Southeast Asia are among the contentious issues set to dominate a major regional forum kicking off this weekend.

The annual diplomatic and security meetings hosted by the Association of Southeast Asian Nations (ASEAN) will this year be held in Brunei against a backdrop of escalating tensions over increasingly assertive Chinese maritime territorial claims.

The foreign minister-level talks, which climax Tuesday with the ASEAN Regional Forum that includes China, the United States, Russia and other heavyweights, are further spiced by the Sino-US spat over fugitive intelligence leaker Edward Snowden.

Snowden’s revelations of US government monitoring of phone and Internet traffic have drawn Chinese criticism, stoking mutual distrust already heightened by the Obama administration’s strategic “pivot” to Asia.

The US has accused China of letting Snowden slip out of Hong Kong, an allegation Beijing disputes. Snowden is now at Moscow’s airport and is said to be seeking asylum in Ecuador.

Russia has angered the United States by refusing to extradite Snowden and the Brunei event is an opportunity for US Secretary of State John Kerry to discuss the issue with his Russian counterpart, Sergei Lavrov.

The meetings begin with a gathering of the 10-member ASEAN bloc tomorrow, expanding Monday to include China, Japan and South Korea, before an East Asia summit gathering 26 countries and the European Union.