A Bush administration official has told North Korea that time is running out for it to act on a nuclear disarmament agreement, a US official said Tuesday, as the weekend deadline approached for Pyongyang to shut down its main nuclear reactor. Victor Cha, President Bush's top adviser on North Korea, made the comments in a meeting with Pyongyang's top nuclear negotiator, Kim Kye Gwan, according to a US official with knowledge of the meeting who spoke on condition of anonymity because of the sensitivity of the talks. "They don't have a lot of time," the official said of the Saturday deadline for North Korea to take initial steps toward dismantling its nuclear program, including closing its main nuclear reactor, in exchange for economic aid and political concessions. "They just can't be in receive mode, they have to be in action mode," the official said after Cha and Kim met Tuesday morning. Cha is part of a US delegation, including Democratic presidential candidate Bill Richardson and Anthony Principi, Bush's former veteran affairs secretary, on a four-day trip to Pyongyang to recover remains of American servicemen killed in the 1950-53 Korean War. But they also have had a series of meetings with Kim to discuss the February agreement, which has been held up by a dispute over North Korean funds frozen in a Macau bank. American nuclear negotiator Christopher Hill has said the financial problem would be a stumbling block for the closure. Kim gave Cha no indication of whether the North would offer any concessions in the face of US pressure or if it would be able to access its money before Saturday, the official said.