UN inspectors have verified that North Korea has shut down its sole functioning nuclear reactor, the chief of the watchdog agency said Monday, confirming Pyongyang's first step to halt production of atomic weapons in nearly five years. "Our inspectors are there. They verified the shutting down of the reactor yesterday," said Mohamed ElBaradei, chief of the International Atomic Energy Agency. "The process has been going quite well and we have had good cooperation from North Korea. It's a good step in the right direction," ElBaradei said, speaking in Bangkok ahead of an event sponsored by Thailand's Science Ministry. North Korea pledged in an international accord in February to shut the reactor at Yongbyon and dismantle its nuclear programs in return for 1 million tons of oil and political concessions. However, it stalled for several months because of a separate, but now-resolved dispute with the US over frozen bank funds. The shutdown over the weekend, confirmed by a 10-member team of IAEA inspectors who arrived in North Korea on Saturday, was the first on-the-ground achievement toward scaling back Pyongyang's nuclear ambitions since the international standoff began in late 2002. The Yongbyon reactor generates plutonium for atomic bombs; North Korea conducted its first nuclear test explosion in October. Earlier Monday, South Korea sent the second of two initial shipments of what eventually will be 50,000 tons of oil to reward North Korea specifically for the reactor shutdown. The first arrived Saturday, prompting North Korea to begin the shutdown of the Yongbyon. The second shipment departed Monday, South Korea's Unification Minister Lee Jae-joung said. The North's Foreign Ministry said Sunday that further progress under the disarmament accord would now depend "on what practical measures the U.S. and Japan, in particular, will take to roll back their hostile policies toward" North Korea. The ministry noted that North Korea shut its reactor even before receiving all 50,000 tons of oil, adding that this was "a manifestation of its good faith towards the agreement," according to a statement carried by the official Korean Central News Agency. North Korea is set to participate in a renewed session of arms talks this week in Beijing, along with China, Japan, Russia, South Korea and the US. Hill, a US assistant secretary of state, has said the negotiations would focus on a "work plan and a timeframe" for how disarmament would proceed, adding that he planned to meet his North Korean counterpart Tuesday ahead of the formal start of talks. A North Korean diplomat said Pyongyang was willing to discuss listing its nuclear programs as well as disabling them as long as the US removed all sanctions against the communist nation. Hill said Monday during his meeting with Lee that Washington moving to remove the North's pariah status would depend on Pyongyang continuing to comply with its disarmament promises. "With complete denuclearization, everything is going to be possible," Hill said. Hill has said he believes the full disablement of the North's nuclear facilities could be completed by the end of the year. A first step will be the North declaring a complete list of its nuclear programs to be dismantled. However, the North has yet to publicly admit to embarking on a uranium enrichment program - which the US in 2002 alleged it had done to spark the nuclear crisis. "A full declaration needs to be full," Hill said Monday. Nuclear envoys cautioned the road ahead would be difficult. "Obviously we've encountered problems in the past and we'll encounter problems in the future," Hill said. "We cannot presume that North Korea will do everything if it is given oil," South Korea's nuclear negotiator Chun Yung-woo said after meeting Hill. "The North is likely to demand political and security incentives as it moves toward denuclearization."