Olli Heinonen, the International Atomic Energy Agency's deputy director general for safeguards speaks to journalists before leaving his hotel in Beijing Tuesday, June 26, 2007. [AP]

"Tomorrow, we're going to Yongbyon," Heinonen told Kyodo, adding that the inspectors would return to Pyongyang on Friday.

The North's permission would be the latest sign that Pyongyang is serious in carrying through its disarmament pledge.

North Korea agreed to close the plutonium-producing Yongbyon reactor in February in exchange for economic aid and political concessions. But North Korea ignored an April deadline to do so because of a banking dispute with the United States.

That dispute has finally been resolved this week after months of delay, and Pyongyang announced Monday that it would move forward with the disarmament deal.

It would be the first time for UN nuclear inspectors to visit Yongbyon since North Korea expelled IAEA monitors in late 2002 after the current crisis broke out with US accusations that Pyongyang had a secret, uranium-based weapons program.

The facility is at the center of international efforts to stop North Korea's nuclear program. The country carried out its first atomic test explosion in October.

The negotiating climate has sparked optimism in North Korea's neighbors.

"After the consultation is over, I think it will be shut down as early as possible," South Korean Foreign Minister Song Min-soon said, referring to the North Korea's reactor.

Song, leaving for Washington for talks with Secretary of State Condoleezza Rice, said the reactor's closure is now a "technical issue," which would not be subject to a "political decision" by North Korea.

Heinonen, whose team arrived in the North's capital on Tuesday, said the officials there who greeted his team at the airport in Pyongyang were friendly and appeared ready for discussions.

"It seems to be a good start," he told The Associated Press in a telephone interview.

He told the broadcaster APTN just after arriving in North Korea's capital that he would be "negotiating arrangements for verification of the shutdown and sealing" of the North's main reactor during the five-day trip through Saturday.

Separately, a delegation of European lawmakers who visited North Korea, told reporters Wednesday in South Korea that the North Korea says it's committed to carrying out its promises on denuclearization.

"We had the real impression that they are willing immediately to shut down and they will start as they promised to do so," Hubert Pirker, who led the five-member European Union delegation to North Korea, told a news conference in Seoul.

As the North began moving on the disarmament deal, South Korea announced Tuesday it would start sending promised food aid to North Korea on June 30.

Assistant Secretary of State Christopher Hill said Saturday he believed the shutdown would happen within about three weeks. Hill is the top US nuclear negotiator with North Korea.

In Manila, a top US general said Wednesday that the US military would help verify whether North Korea would shut down the Yongbyon reactor as promised and if it would try to move its operations elsewhere.

"We will try to verify the shutdown of Yongbyon in support of and in coordination with other agencies like the IAEA," US Pacific Commander Timothy Keating told a news conference. "You bet, we're gonna pay very close attention."