The Philippine embassy in China has warned its citizens to beware of personal "threats" and avoid political debates ahead of a tribunal ruling Tuesday over a bitter dispute in the South China Sea.

It is time for China to do a #CHexit from the South China Sea, social media users and activists in the Philippines said Monday on the eve of a crucial tribunal ruling.

An Asia-Europe summit later this week is no place for talking about the South China Sea, Beijing said Monday on the eve of an international tribunal ruling in the dispute.

The Philippines is willing to share natural resources with Beijing in contested South China Sea areas even if it wins a legal challenge next week, Foreign Secretary Perfecto Yasay told AFP Friday.

Beijing will not take a "single step back" in the contested South China Sea, state-run media said Friday, despite reports of US naval patrols close to its artificial islands ahead of a tribunal ruling in the dispute.

Beijing must prepare for "military confrontation" in the South China Sea, state-run media said Tuesday, as it began naval drills in the area ahead of an international tribunal ruling over the maritime dispute.

China will never compromise on sovereignty, President Xi Jinping said Friday ahead of an international tribunal ruling over Beijing's maritime claims, as he celebrated the Communist Party's 95th anniversary.

Beijing will reject any ruling by an international tribunal in a contentious case brought by the Philippines over the South China Sea, the foreign ministry said, as tensions mount over the disputed waters.

President Joko Widodo visited remote Indonesian islands on a warship Thursday in an apparent show of force after clashes with Chinese vessels and as fears grow Beijing is seeking to stake a claim in nearby waters.

"Our stand to uphold the International Law is very consistent, and we have the obligation to abide by the tribunal's decision whether we like it or not."