Washington ? Intelligence officials suspect that Russia, Pakistan and China are suppliers of equipment North Korea has used to develop its nuclear weapons program, an allegation Moscow and Islamabad quickly denied Friday.

“This has absolutely nothing to do with reality,” said Russian Foreign Ministry spokesman Alexander Yakovenko.

“No exchange of any sort was done with North Korea,” said Gen. Hamid Gul, a former chief of Pakistan’s spy agency, Inter-Services Intelligence. “North Korea’s technology has always been ahead of ours … North Korea has always been close to China and Russia … we are in no position to help them.”

Two U.S. officials said Friday that while China is believed to be among North Korea’s sources, Pakistan and Russia are its main suppliers of equipment needed to enrich uranium for nuclear weapons. Some of the equipment has industrial as well as military uses and passes through countries that may not know what North Korea is doing with it.

White House spokesman Ari Fleischer would not comment on a New York Times report that Pakistan, in the late 1990s, forged a deal supplying Pyongyang with the equipment in exchange for North Korean missiles.

But he said: “Since Sept. 11, many things that many people may have done years before Sept. 11 … have changed.” Pakistan has become a major ally among the 90-nation anti-terror coalition established since the Sept. 11 attacks on America.

Another official, asking not to be identified, confirmed that Pakistan has carried out exchanges with North Korea on weapons technology but said they took place before President Pervez Musharraf took office in 1999.

Pressing suppliers to deprive North Korea of nuclear-related equipment will have to be part of the intense diplomatic effort launched by the Bush administration, since North Korea startled officials with the admission it has been secretly pursuing its nuclear program despite agreeing not to, one analyst said.

The administration is working to form an international coalition to steer North Korea away from its decision to pursue nuclear weapons.

Sen. John McCain said Friday he thought economic sanctions ought to be leveled immediately against Pyongyang.

Construction continues on a light water reactor project by the Korean Peninsula Energy Development Organization at Kumho in North Korea's northeastern coastal area in this Aug. 7, 2002, file photo. Under a 1994 deal, energy-starved North Korea agreed to freeze a suspected nuclear weapons program in return for two modern, light-water reactors built by a U.S.-led consortium. North Korea announced this week that it was pursuing a nuclear weapons program, and the United States suspects Pakistan, China and Russia provided assistance.

“I’m not ruling out the military,” he said on NBC’s “Today” show, “but there are other actions that would have to be tried first. And I believe that strong economic sanctions could bring down that government.”

The U.S. diplomatic offensive began not long after the administration disclosed Wednesday that North Korea had acknowledged, during bilateral talks earlier this month, that it was attempting to develop nuclear weapons.

Two top State Department officials, John Bolton and James Kelly, flew Thursday to Beijing for talks with Chinese officials.

China is a major trading partner of North Korea’s and perhaps the one country capable of extracting concessions from the communist nation through economic sanctions, an administration official said.

President Bush is expected to raise the issue with Chinese President Jiang Zemin next week when they meet at Bush’s ranch in Texas.

Kelly plans consultations in Japan and South Korea on North Korea. Bolton’s itinerary includes stops in Russia, Britain and France, all nuclear powers which may have views on how to influence North Korea.