President Barack Obama warned Chinese President Hu Jintao that Washington would have to redeploy forces in Asia unless Beijing stepped up pressure on North Korea, The New York Times reported Friday.

The US "warning, first made in a phone call to Mr Hu last month and repeated over a private dinner at the White House on Tuesday, persuaded China to take a harder line toward North Korea," the report said citing an unnamed US official.

It said the push seeking action from the visiting Chinese leader "opened the door to a resumption of dialogue between North and South Korea."

On Thursday, Seoul said that it had agreed to hold defense talks with the North, the first engagement between the Koreas since a deadly North Korean artillery attack on a South Korean island in November. The strike lurched the peninsula seemingly to the brink of war.

While China has not condemned North Korea for torpedoing a South Korean warship, Hu on his visit did for the first time join the United States in voicing concern at "a new North Korean uranium-enrichment plant. But there were no immediate signs that it planned to punish the North for its defiance," the report added.

Pressure from the US president "reinforced by cabinet members like Defense Secretary Robert M. Gates, moved China into much closer alignment with the United States in dealing with North Korea."

"Without help from China, which is the major supporter of the North Korean government, Mr Obama told Mr Hu that the United States would have to take long-term measures, like redeploying its forces, changing its defense posture or beefing up military exercises in Northeast Asia," the unnamed administration official told the Times.

"It was not meant to suggest pre-emption, but we were projecting that a North Korea that becomes a national security threat is going to get a response," the report quoted the unnamed official as saying. "That was attention-getting for the Chinese."

White House spokesman Robert Gibbs did not confirm the report, but said that the US side had tried to get China to understand its deep concerns over North Korea's actions.

"We have... worked to express our concern about the aggressive activities of North Korea and to work to bring the Chinese effectively into helping us deal with some of those problems," he told reporters on Air Force One.

Washington irked Beijing last year when it sent the aircraft carrier George Washington to take part in joint drills with South Korea in the Yellow Sea after Pyongyang sunk a warship from the South.

South Korea meanwhile pressed North Korea Friday to discuss its nuclear weapons program, a day after the two nations agreed to hold high-level military dialogue to ease months of tensions.

Analysts were cautious about prospects for negotiations, which would be the first since the North sparked outrage in the South with a deadly bombardment of a border island last November.

Cross-border relations have been sour since a conservative government in Seoul linked major aid to the North's nuclear disarmament.

They worsened sharply last May when the South accused the North of torpedoing a warship with the loss of 46 lives, a charge Pyongyang denies.

Tensions rose even higher after the North bombarded Yeonpyeong island near the disputed border, killing four people including civilians.

The North said the attack was in response to an artillery drill by the South, which dropped shells into what Pyongyang claims as its waters.

In an abrupt change of tack, Pyongyang this year has repeatedly called for talks.

Seoul's unification ministry stuck to its terms for dialogue -- that the North accept responsibility for the two attacks, promise no repetition and show sincerity about nuclear disarmament.