North Korea, Pakistan, and India are three such examples in the case of nuclear weapons and missile technology. In October 2002, the Bush Administration announced that North Korea had been pursuing a clandestine uranium enrichment program; U.S. intelligence officials leaked to the press a few days later that Pakistan, among other countries, was implicated. Pakistani government officials denied such trade. Both North Korea and Pakistan have been subject to sanctions in the past for WMD trade. Neither state lies completely outside the nonproliferation regimes. By the mid-1990s, however, North Korea had a proven track record in ballistic missiles, and Pakistan had demonstrated its uranium enrichment capabilities. Although Pakistan apparently was hampered by a lack of hard currency, it could provide North Korea with a route to nuclear weapons using highly enriched uranium (HEU). This route would not only circumvent North Korea's Agreed Framework with the United States, but would also be difficult to detect using satellite imagery. North Korean Enrichment

At the time the 1994 Agreed Framework with North Korea was negotiated, there was concern about, but scant evidence of, North Korean interest in uranium enrichment. In the Deputy Director of National Intelligence's report, "Unclassified Report to Congress on the Acquisition of Technology Relating to Weapons of Mass Destruction and Advanced Conventional Munitions," 1 January-31 December 2004 (pursuant to Section 721 of the of the FY1997 Intelligence Authorization Act), there is no mention of any North Korean uranium enrichment activity or capability. Media reports suggested that the CIA had evidence of construction and of procurement. The second development program has been headed by Khan Research Laboratories. Pakistan now fields approximately 5 to 10 of these missiles and is developing longer-range variants. These solid-fueled, medium-range missiles apparently are based on Chinese M-11s. Pakistan's Nuclear Sales

The genesis of Pakistan's nuclear cooperation with North Korea is murky. There are a few reports in trade journals of equipment passing through Pakistan on the way to North Korea, but it is difficult to pinpoint when cooperation began. One report says that cooperation between Pakistan and North Korea expanded into the nuclear and missile areas in Benazir Bhutto's second term (1993 to 1996) to include exchanges of scientists and engineers. In a letter to key senators and members of Congress on March 12, 2003, Assistant Secretary of State for Legislative Affairs Paul Kelly wrote that "the Administration carefully reviewed the facts relating to the possible transfer of nuclear technology from Pakistan to North Korea, and decided that they do not warrant the imposition of sanctions under applicable U.S. Issues for Congress

North Korea's actions alone raise significant policy questions for Congress, specifically, on how to roll back a capability that North Korea refuses to admit it has. Second, this example of secondary proliferation highlights the critical roles of sanctions, interdiction, and intelligence. The example of WMD trade between North Korea and Pakistan raises particular questions about how to interpret proliferation threats within the nexus of terrorism and WMD.
In October 2002, the United States confronted North Korea about its alleged clandestine uranium enrichment program. Soon after, the Agreed Framework collapsed, North Korea expelled international inspectors, and withdrew from the Nuclear Nonproliferation Treaty (NPT). U.S. intelligence officials claimed Pakistan was a key supplier of uranium enrichment technology to North Korea, and some media reports suggested that Pakistan had exchanged centrifuge enrichment technology for North Korean help in developing longer range missiles.
U.S. official statements leave little doubt that cooperation occurred, but there are significant details missing on the scope of cooperation and the role of Pakistan's government. North Korea and Pakistan both initially denied that nuclear technology was provided to North Korea; President Musharraf admitted, however, in 2006 that such technology had been transferred. This report describes the nature and evidence of the cooperation between North Korea and Pakistan in missiles and nuclear weapons, the impact of cooperation on their weapons of mass destruction (WMD) programs and on the international nonproliferation regime. It will be updated as events warrant.
The roots of cooperation are deep. North Korea and Pakistan have been engaged in conventional arms trade for over 30 years. In the 1980s, as North Korea began successfully exporting ballistic missiles and technology, Pakistan began producing highly enriched uranium (HEU) at the Khan Research Laboratory. Benazir Bhutto's 1993 visit to Pyongyang seems to have kicked off serious missile cooperation, but it is harder to pinpoint the genesis of Pakistan's nuclear cooperation with North Korea. By the time Pakistan probably needed to pay North Korea for its purchases of medium-range No Dong missiles in the mid-1990s (upon which its Ghauri missiles are based), Pakistan's cash reserves were low. Pakistan could offer North Korea a route to nuclear weapons using HEU that could circumvent the plutonium-focused 1994 Agreed Framework and be difficult to detect.
WMD trade between North Korea and Pakistan raises significant issues for congressional oversight. Are there sources of leverage over proliferators outside the nonproliferation regime? Do sanctions, interdiction, and intelligence as nonproliferation tools need to be strengthened? How is the threat of proliferation interpreted within the nexus of terrorism and WMD? Further, has counterterrorism cooperation taken precedence over nonproliferation cooperation? If so, are there approaches that would make both policies mutually supportive?
See also CRS Report RL33590, North Korea's Nuclear Weapons Development and Diplomacy, by [author name scrubbed], and CRS Report RS21391, North Korea's Nuclear Weapons: Latest Developments, by [author name scrubbed].