KUALA LUMPUR, Malaysia >> The United States and China clashed Wednesday over who is to blame for rising tensions over territorial disputes in the South China Sea with Washington demanding a halt to “problematic actions” in the area and Beijing telling foreign parties to keep out.

In blunt but diplomatic terms, U.S. Secretary of State John Kerry and his Chinese counterpart Wang Yi suggested that efforts to ease tensions over competing claims remained a contentious work in progress despite hopes for movement on ways to resolve them here at a Southeast Asian regional security forum.

Kerry urged China to end provocative land reclamation projects in the South China Sea that have ratcheted up tensions with its smaller neighbors in some of the world’s busiest commercial sea lanes.

Wang, meanwhile, sent a strong message that those without claims, such as the United States, should allow China and the other claimants to deal with them on their own.

Kerry told foreign ministers of members of the Association of Southeast Asian Nations that the U.S. shares their desire “to ensure the security of critical sea lanes and fishing grounds, and we want to see that disputes in the area are managed peacefully and on the basis of international law.” A senior U.S. official said Kerry made the case for easing tensions in a closed-door meeting with Wang.

In his meeting with Wang, Kerry reiterated U.S. concerns about the rising tensions and “China’s large scale reclamation, construction, and militarization of features,” according to the senior U.S. official.

The official said Kerry had “encouraged” China, and the other claimants, “to halt problematic actions in order to create space for diplomacy.” The official spoke on condition of anonymity because he was not authorized to speak publicly about the private meeting.

Chinese land reclamation in contested waters has irked Southeast Asian nations who, like the U.S., want China to stop. Washington is calling for a halt to aggressive actions by China and other claimants to allow a diplomatic solution to the rift. The U.S. is not a party to the conflict but says a peaceful resolution of the problem and freedom of navigation are in the U.S. national interest.

China rejects any U.S. involvement and insists it has the right to continue the reclamation projects. Beijing was opposed to the issue being raised at the security forum in the first place.

Kerry told the ASEAN ministers that his meeting with Wang had been “good” and that he hoped “we will find a way to move forward effectively, together, all of us” over the course of the two-day forum.

But Wang gave no indication he had been swayed by Kerry, telling reporters later that foreign parties should support Beijing and ASEAN’s plan to accelerate negotiations on a code of conduct governing behavior in the disputed waters.

“We want to send a clear message to the international community that China and ASEAN have the capability and wisdom to resolve this specific issue between us,” he told a news conference. “We shouldn’t allow the South China Sea region to be destabilized.”

He said that China is committed to a peaceful solution through “rules and mechanisms already in place.” He also pledged that China will uphold freedom of navigation and overflight at sea. “There has not, and will not be any problem in this regard,” he said.

However, ASEAN members have complained that although China has pledged to start substantive negotiations with them on a code of conduct governing behavior in the resource-rich and busy waterways, there is a gap between its pledge and the situation on the ground.

China, Taiwan and several ASEAN members — the Philippines, Malaysia, Vietnam and Brunei — have wrangled over ownership and control of the South China Sea in a conflict that has flared on and off for decades.

Tensions rose last year when China began building artificial islands in the Spratly Islands, which the U.S. and Beijing’s rival claimant countries fear could impede freedom of navigation and overflights in a major transit area for the world’s oil and merchandise.

The disputes have led to deadly confrontations between China and Vietnam, and Washington and governments in the region are concerned that greater military deployments increase the risk of miscalculations and accidental clashes that could spiral out of control.

U.S. officials say China has reclaimed more than 3,000 acres (1,200 hectares) in the last 18 months alone. That figure dwarfs the 100 acres (40 hectares) that Vietnam, Malaysia, the Philippines and Taiwan have reclaimed in disputed areas over the last 45 years.

Wang bristled when asked about calls for China to halt its island-building activities.

“China has stopped, China has stopped. You want to see who is building? Take a plane and go see who is still building.” he said.