BEIJING, May 30 (Xinhua) -- Top U.S. negotiator Christopher Hill arrived in Beijing on Wednesday, saying it is time to resolve the dispute over the frozen funds of the Democratic People's Republic of Korea (DPRK).

    The issue involving the Macao-based Banco Delta Asia (BDA) had been "very difficult", Hill told reporters on his way to a dinner with Chinese Vice Foreign Minister Wu Dawei, who heads the Chinese delegation at the six-party talks on the Korean nuclear issue.

    "It involves legal issues and bank regulatory issues and it's not proven easy to solve," Hill said.

    Hill met with Wu Dawei and other officials of the Chinese Foreign Ministry on Wednesday. He will leave the Chinese capital on Thursday, according to the U.S. embassy.

    Despite the little progress on the BDA issue, Hill said he still felt positive about the six-party talks framework.

    He said the BDA issue was of a "technical nature" and it was very useful to exchange views with the Chinese side. Cooperation between the two countries was "one of the strongest aspects" of the six-party talks process.

    "We need to put our heads together to find the solution," the U.S. chief negotiator said.

    Under an agreement adopted by the six parties during the most recent talks on Feb. 13, the DPRK was supposed to shut down and seal the Yongbyon facilities within 60 days in exchange for 50,000 tons of heavy fuel oil or equivalent aid.

    The DPRK, which missed the April 14 deadline, insisted that its 25 million dollars frozen at the BDA must be returned before closing Yongbyon and starting new negotiations.

    Hill said on leaving his hotel on Wednesday morning that he had been in touch with the Chinese side in the last few weeks, adding, "it's time to sit down" and try to resolve the funds issue.

    The U.S. top negotiator said he was waiting for the schedule to be implemented; referring to DPRK 's shutdown of its nuclear facilities.