WASHINGTON – The Obama administration urged China to press North Korea to halt provocative actions against South Korea, after an artillery attack that the U.S. called a “premeditated” violation of the truce that ended the Korean War.

As the isolated North’s only ally and main economic partner, China plays a “pivotal” role in reducing tensions and has a duty to tell Pyongyang that deliberate acts “specifically intended to inflame tensions in the region” are not acceptable, the State Department said.

“China is pivotal in moving North Korea in a fundamentally different direction,” State Department spokesman P.J. Crowley told reporters. “We expect China to be clear, like we are, as to where the responsibility for the current situation, the current tension lies. This is something that we feel strongly about.”

He said U.S. diplomats had delivered that message to Chinese officials in Washington and Beijing in the aftermath of Tuesday’s North Korean artillery attack on a South Korean island that killed two South Korean troops and two civilians and aggravated tensions between the rival Koreas.

Secretary of State Hillary Rodham Clinton is expected to discuss the attack and the response to it by telephone with China’s foreign minister, Crowley said.

Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, echoed the point of China’s importance in the process in an interview to be aired Sunday on CNN’s “Fareed Zakaria GPS.”

“We really think it’s important for the international community to lead, but in particular China,” Mullen said. “It’s a very dangerous area when he (North Korean leader Kim Jong-il) does this, it destabilizes the region, and China has as much to lose as anybody in that region with the continuation of this kind of behavior and what the potential might be.”

The U.S. has frequently called on China to press North Korea to stop its belligerent actions toward South Korea and Japan, with limited success.

China has backed U.N. resolutions punishing North Korea for nuclear tests but issued only a muted response to the March sinking of a South Korean warship that an international investigation blamed on the North. North Korea has denied the allegation.

China said Wednesday that it was “highly concerned” about the artillery exchange and urged restraint.

China “feels pain and regret about an incident causing deaths and property losses and is worried about the developments,” Foreign Ministry spokesman Hong Lei said. “We have always maintained that the relevant parties should, through dialogue and consultation, resolve disputes by peaceful means.”

Some American officials and independent analysts have questioned the amount of influence that China actually has with its neighbor and warned against relying on the Chinese to change North Korean actions.

But on Wednesday, the administration was firm that China has to do what it can to reduce tensions even as it acknowledged that Beijing may not be able to “dictate” to Pyongyang.

“This is a clear case where North Korea has to be given a consistent, unified message” that “these provocations are unwarranted, unhelpful and should cease,” Crowley said. “That was our message yesterday to China.”

The top U.S. envoy for North Korea policy, Stephen Bosworth, met with Chinese officials in Beijing earlier Wednesday.