The top U-S negotiator to the six-way talks on North Korea's nuclear program says the U-S government has not set any deadline on the North's return to the stalled meeting.

Christopher Hill, assistant secretary of state for East Asian and Pacific affairs, said Monday that Washington not move back from its original position to bring Pyongyang back to the negotiating table.

Speaking at a press conference, he said the North is reluctant to set any specific date for a return, and Washington is weighing several options if the talks collapse.

Hill warned, however, that time will eventually force a final option, and it could be giving up and walking away from the situation.