Seoul  -  For the second time in three weeks a US delegation Thursday has headed to Pyongyang in a diplomatic push for North Korea to meet pledges and resume six-way talks on the nuclear crisis.

Led by Sung Kim, the US State Department's top Korea expert, the delegation crossed the inter-Korean border for Pyongyang Thursday, according to the US embassy in Seoul.

The US State Department had announced earlier that Sung's planned discussions were "part of the current dialogue" concerning agreed upon declarations of all nuclear activity in North Korea.

Sung, who last visited Pyongyang in April, is expected to receive from North Korea a declaration of its nuclear stockpiles, Yonhap news agency reported, citing a South Korean government official.

It remains unclear whether it is a final version or if further discussions will be necessary.

North Korea must provide the declaration before the six-way talks - involving North and South Korea, the US, Japan, China and Russia - which have been suspended for months, resume.

Pyongyang did submit details of its nuclear weapons programmes to the US late last year, however, it was rejected as it did not mention suspected uranium-enrichment program and proliferation to Syria. North Korea denies the allegations.

The Syrian nuclear plant is likely to have been destroyed by Israeli warplanes last year.

If Pyongyang does submit the declaration, Washington will begin the process of removing North Korea from its list of state sponsors of terrorism, reported Yonhap news agency. (dpa)