The dispute over the South China Sea has been brewing in one way or another for decades, with China, Vietnam, Philippines, Malaysia and Taiwan all laying competing claims to parts of the sea, which is believed to hold valuable oil and minerals.

But the tensions have escalated as China’s military has grown stronger and bolder in making its assertions. Of all the countries, China’s claim is by far the largest, covering a huge U-shaped area over the entire region.

In recent days, tensions have become particularly serious, with China and Vietnam hurling accusations and threats at each other, and with both countries backing up those threats by launching or announcing military drills in disputed waters.

On Monday, in a rare move, Singapore issued a statement on the issue, urging all parties to act with restraint and telling China to spell out its territorial claims in a precise fashion.

“We think it is in China’s own interest to clarify its claims in the South China Sea with more precision as the current ambiguity…has caused serious concerns in the international maritime community,” the Singaporean Foreign Ministry said.

Meanwhile, at a crowded forum in Washington to discuss the recent flare-ups, the ambassador from Indonesia – another country with no claims -- said China and the other countries fighting over the territories need to include other countries in the process.

“It should not turn into a matter just between the claiming states, because the bottom line is that whatever happens there will affect security to the entire region,” said Ambassador Dino Patti Djalal.

U.S. officials have been leery of being drawn into the conflict. Two senior defense officials attending the same forum as Djalal stuck close to their script, issuing only a few statements that avoided taking sides and encouraging all parties to calm down.

“It’s not for us, the U.S., to implement these mechanisms in dealing with various claims on the South China Sea,” said one of the U.S. defense officials, who said he was not authorized to speak on the record.

A group of U.S. senators, however, including Jim Webb (D-Va.) and John McCain (R-Ariz.) have been outspoken on the issue.

“I think we in our government have taken too weak of a position on this,” Webb, who introduced a resolution to condemn China’s use of military force in the South China Sea, said earlier this month at the Council on Foreign Relations. “When we say the United States government doesn’t have a position on sovereignty issues, not taking a position is taking a position.”

[An earlier version of this post incorrectly stated that McCain was among the senators to introduce the resolution.]

The most serious confrontation in the region this year began a few weeks ago when, according to Vietnam, China pursued a Vietnamese seismic survey boat, damaging a research cable trailing the ship.

China responded by ordering Vietnam to stop any and all oil-explorations in the sea. The insults and live-fire drills between the two began shortly after.

“Unfortunately, the reality is that we are quite a long ways from the point where any of the parties are ready to sit down and negotiate,” said Indonesian Ambassador Djalal of the recent rising tensions. “This saber-rattling is likely to continue. We will have skirmishes of greater and greater intensity.”