Already scrambling to confront multiple simultaneous international crises, the Obama administration stepped up efforts Saturday to avert another, as U.S. Secretary of State John Kerry called on China and its smaller neighbors to take new steps to ease tensions over maritime disputes in Asian waters that many fear could spark conflict.

Amid new American military action in Iraq, fears of a Russian invasion of east Ukraine and the ongoing war between Israel and Hamas, Kerry formally presented a proposal under which China and members of the Association of Southeast Asian Nations that have competing claims to territory in the South China Sea would voluntarily halt provocative actions.

Recent activity by several claimants, particularly China, in disputed areas has heightened concerns about confrontation, which would destabilize the Asia-Pacific, interfere with international maritime commerce and roil the global economy.

"The United States and ASEAN have a common responsibility to ensure the maritime safety of critical global sea lanes and ports," Kerry told ASEAN foreign ministers, including those from claimant states Brunei, Malaysia, the Philippines and Vietnam, on the sidelines of an annual regional security forum.

"We need to work together to manage tensions in the South China Sea and manage them peacefully and also to manage them on a basis of international law," he said.

ASEAN has generally backed U.S. suggestions on easing tensions, including endorsing the development of a binding code of conduct to govern activities involving conflicting claims. But China has resisted and progress on the code of conduct has been halting if best over the past several years.

Earlier Saturday, the Philippines, a U.S. treaty ally, presented a three-point initiative that incorporated the American concept of a voluntary end to tension-producing activities.

"Tensions in the South China Sea have worsened in the past few months and continue to deteriorate," said Philippines Foreign Secretary Albert del Rosario. "All of us are seeing an increased pattern of aggressive behavior and provocative actions in the South China Sea, seriously threatening the peace, security, prosperity and stability in the region."

In addition to the immediate voluntary cessation of provocative acts, Manila's "Triple Action Plan" calls for the speedy conclusion of the long-delayed code of conduct as well as long-term arbitration over disputes that would eventual resolve the claims under the U.N. Law of the Sea.

As expected, however, China reacted coldly to the Filipino proposal, saying that the tensions were being overblown.

"Someone has been exaggerating or even playing up the so-called tension in the South China Sea," Chinese Foreign Minister Wang Yi told reporters. "We do not agree with such a practice, and we call for vigilance in the motives behind them."

Among the recent provocative actions cited by the U.S. and ASEAN members was China's deployment of a deep-sea oil rig in early May near the Paracel islands, which are claimed by both Hanoi and Beijing. Although the Chinese removed the rig two months later, the incident continues to rankle Vietnam.

Washington is concerned that while China's withdrawal of the rig in mid-July had removed an irritant, it had left a legacy of anger and strained relations with Vietnam and likely raised serious questions among China's other neighbors about its long-term strategy.

China says it has a historical right to most of the South China Sea and resents what it sees as U.S. meddling.