Russian Foreign Ministry spokesman Mikhail Kamynin said such steps "will allow us to more effectively settle the denuclearization of the Korean peninsula."
The North said last week it would consider closing down the reactor as soon as it received the first shipment of oil from South Korea under a February aid-for-disarmament deal.
The North's KCNA news agency cited one of its spokespeople today as saying the reactor was shut down after Pyongyang received the first shipment of oil.
In Washington, White House national security adviser Stephen Hadley said it appeared Yongbyon, which produces weapons-grade plutonium, had been shut down.
UN inspectors were due to begin testing today whether Yongbyon had stopped operating.
U.S. envoy Christopher Hill says Washington regards the reactor shutdown as "just the first step" toward nuclear disarmament in a deal for fuel and other aid to North Korea.
Hill has announced plans to meet on July 17 with his North Korean counterpart.
Copyright (c) 2006. RFE/RL, Inc. Reprinted with the permission of Radio Free Europe/Radio Liberty, 1201 Connecticut Ave., N.W. Washington DC 20036. www.rferl.org
Pictures for this story
