The United States said on Tuesday that it has agreed with other parties to the six-party talks to give the Democratic People's Republic of Korea "a bit more time" to fulfill its promise to shut its major nuclear facility.

"I would say that we are being flexible. There is some delays in the process and we're willing to give it a bit more time," State Department spokesman Sean McCormack said of Pyongyang's missing the deadline to shut its Yongbyon reactor.

"We haven't received any formal notification from the North Koreans that they are at this point taking steps to fulfill their obligations under the Feb. 13 agreements: shutting down and sealing the Yongbyon plant," he said.

The spokesman also declined to comment on reports that U.S. spy satellites on Monday spotted unusual movement of people and vehicles around the cooling tower and parking lot at Yongbyon.

U.S. and South Korean officials reportedly believed that the unusual movement by the DPRK has something to do with activities to close down the Yongbyon reactor.

The DPRK has insisted it will begin shutting nuclear facility and readmit inspectors of the International Agency of Atomic Agency once it has retrieved 25 million dollars in funds frozen in Macao's Banco Delta Asia.