BEIJING, Feb. 12 (Xinhua) -- The six parties involved in the Korean Peninsula nuclear issue on Monday made their final attempt to clinch a deal, but no breakthrough was announced till late night.

    The talks entered the fifth day on Monday with energy aid still as the focus of negotiations.

    Instead of returning to their hotels, all chief negotiators stayed in the State Diaoyutai Guesthouse by late Monday night.

    A series of one-on-one talks were held after the supper, involving the Democratic People's Republic of Korea (DPRK) and the United States, according to the press center.

    "The result will come out soon," a Chinese envoy said on condition of anonymity late Monday.

    Yet envoys were said to be debating on whether to extend the negotiations for another day.

    An official from the Republic of Korea (ROK) delegation said Monday afternoon that the talks cannot foresee an optimistic result as consultations are stretched into the end of what is expected to be the final day of negotiations.

    The official, on condition of anonymity, said the ROK has not heard from China that the talks would conclude on Monday and the parties are still discussing a preliminary Chinese draft.

    The draft, circulated on Thursday, reportedly proposes halting within two months the work at nuclear sites in the DPRK, including the Yongbyon reactor, and supplying Pyongyang with alternative energy sources.

    "It is the last day of the talks, let's see how it goes," said chief U.S. negotiator Christopher Hill. "We have put everything on the table, it's up to the DPRK."

    The ROK chief negotiator Chun Yung Woo cautioned the prospect of the talks on Monday morning.

    "The sky in Beijing is very clear, but the prospect for the six-party talks is unclear," Chun told reporters in the hotel.

    At a chief delegates' meeting on Sunday, the DPRK agreed with the other parties to conclude the talks on Monday. "This shows the DPRK has the will to achieve results today," said Chun.

    But whether the talks will conclude Monday depends on what the attitude the DPRK will take, Chun added.

    Echoing Chun's remarks, Japanese negotiator Kenichiro Sasae said the parties will make utmost efforts to reach an agreement as the talks are stretched to the final day on Monday.

    "However, whether or not an agreement will be reached depends on response from the DPRK," said Sasae.

    To coordinate differences, host China held separate bilateral meetings with the DPRK and the United States on Monday morning. And the DPRK and the United States also held their one-on-one meeting, according to the press center.

    "The talks now hinge on the differences on an agreement," said another official from the ROK delegation, adding that the envoys have held random contacts on Monday morning in efforts to strike a deal.

    "It's hard to say we should be optimistic or pessimistic at present," said the official Monday morning.

    Envoys from China, the DPRK, the United States, the ROK, Japan and Russia reconvened the talks on Thursday in Beijing in the wake of a 48-day recess.

    But the talks got blocked by the energy aid to the DPRK after the negotiators held consultations on a Chinese draft, which involves the moves the DPRK will take to abandon its nuclear program in return for economic aid and security guarantee.