The US delegation led by Michele Flournoy, under-secretary for defence, was also expected to push for closer US-China defence ties following concerns in Washington over Beijing's expanding military and recent stand-offs at sea.

"China and the US discussing the situation on the Korean Peninsula is a natural thing and we take this consultation very seriously, and hope that we can get positive results out of it," Chinese foreign ministry spokesman Qin Gang told reporters.

Flournoy met with Ma Xiaotian, deputy chief of the general staff of the People's Liberation Army, at the start of the closed-door talks Tuesday, a US embassy spokeswoman told AFP, without providing further details.

Both sides were to brief the press separately on Wednesday.

A Pentagon official, who spoke on condition of anonymity, told reporters in Washington over the weekend that "North Korea will factor in very strongly" in the talks.

"We would hope that China would use whatever influence they have with North Korea to convince them to change their behaviour," he added.

The UN Security Council earlier this month imposed new financial sanctions on North Korea after Pyongyang last month carried out its second nuclear test and several missile launches.

China, which borders North Korea, is the isolated state's main ally.

Beijing has always favoured cautious diplomacy with Pyongyang, wary of causing its hardline regime to collapse, potentially sending millions of refugees streaming over its border. However, it supported the UN resolution.

North Korea has reacted defiantly to the sanctions by vowing to build more nuclear bombs, scuppering international efforts to denuclearise it.

The meetings come amid recent tensions in Sino-US military relations with vessels confronting each other in tense standoffs in the South China Sea this year.

The confrontations triggered US accusations of "aggressive" Chinese behavior while China complained the US navy had violated maritime law.

The US official said Washington wanted more high-level visits by Chinese defence officials to the United States "so we can understand their continuing (military) build-up."

The China Daily quoted a Chinese military source as saying both sides had "the same need for cooperation," adding the talks would also touch on Afghanistan and Taiwan.

China cut off military exchanges between the two countries in October 2008 over planned US arms sales to Taiwan, a self-governed island that China claims as part of its sovereign territory.

The two sides, however, resumed military talks in February.

Shi Yinhong, director of the Centre for American Studies at Beijing's People's University, told AFP China's key concern in the talks was new US President Barack Obama's stance on Taiwan.

"China is concerned about... whether the US will change its Taiwan policy and the potential arms sales to Taiwan," he said.

The United States has regularly sold arms to Taiwan in the past, in what it says is a bid to preserve stability across the strait, but the moves have always angered China.