“This year, they are particularly under greater threat as a result of compounding risks arising from the unpredictable conduct of states, major power rivalries and frictions.”

China claims about 80 per cent of the sea including large swathes of Vietnam’s exclusive economic zone, or EEZ, as well as the Paracel Islands and Spratly Islands. It also overlaps the EEZs of Asean members Brunei, Indonesia, Malaysia and the Philippines.

Since mid-August, the US has repeatedly riled China by sending warships to the South China Sea and has blacklisted 24 Chinese entities over their involvement in building and militarising artificial islands.

The deal, which comes at a time when tensions over the US election result leave questions over Washington’s engagement in the region, is likely to cement China’s position more firmly as an economic partner with Southeast Asia, Japan and Korea, and put it in a better position to shape the region’s trade rules.

The pact, which was first proposed in 2012 and viewed as a Chinese-led rival to a now-defunct US trade initiative, loops in 10 Southeast Asian economies along with China, Japan, South Korea, New Zealand and Australia.

“After eight years of negotiating with blood, sweat and tears, we have finally come to the moment where we will seal the RCEP Agreement this Sunday,” Malaysia’s Trade Minister Mohamed Azmin Alisaid before the meeting.

“It certainly lends advantage to China’s geopolitical ambitions,” said Alexander Capri, a trade expert at the National University of Singapore Business School.

What is RCEP and what does an Indo-Pacific free-trade deal offer China?

“Think of the Biden administration as sort of a continuation of the Obama administration, certainly when it comes to the pivot to Asia,” he said.

India had been due to sign the pact but pulled out last year over concerns about cheap Chinese goods entering the country, though it can join at a later date if it reverses its position.

Additional reporting by Agence France-Presse