The chief U.S. nuclear envoy, Christopher Hill, who is paying his first visit to the Democratic People's Republic of Korea (DPRK), will urge the DPRK leadership to quickly dismantle its nuclear weapons program, the State Department said Thursday.

Hill will sit down with the DPRK leadership "to convey directly to them the importance of fulfilling their (nuclear) commitment," State Department spokesman Sean McCormack said.

"We are serious about trying to move the process forward, to testing the proposition that North Korea has made that strategic decision to dismantle its nuclear program. So, we'll see how the process proceeds," McCormack said.

McCormack made the remarks after Hill paid a surprise visit to Pyongyang on Thursday ahead of the expected resumption of talks on halting the DPRK's nuclear weapons program.

The trip was Hill's first to the DPRK, as well as the first by a U.S. nuclear envoy since the latest crisis with the DPRK over its nuclear development began in late 2002.

Under the agreement by the six-party talks reached on Feb. 13, the DPRK will shut down and seal its Yongbyon nuclear facility in return for aid and other guarantees, including a possible normalization of ties with the United States.