By successfully firing a rocket that put a satellite in space, North Korea let the far-flung buyers of its missiles know that it is still open for business. But Pyongyang will find that customers are hard to come by as old friends drift away and international sanctions lock down its sales.

North Korea's satellite and nuclear programs were masterminded by the late leader Kim Jong Il, who ruled for 17 years under a ``military first'' policy and died a year ago Monday. An offshoot of the policy was a thriving arms business, including the sale of short and medium-range missiles. The buyers were mostly governments of developing countries _ Myanmar, Iran, Syria, Gulf and African nations _ looking for bargains.

But sustained Western diplomatic pressure and international sanctions imposed since North Korea first conducted a nuclear test in 2006 have cut into its traditional markets in the Middle East. North Korea is also losing business in Myanmar, which has committed to cutting military dealings with Pyongyang as a price for improved relations with the West. Also, there's shrinking demand for the kind of poor quality, Soviet-type weaponry of 1960s and 1970s vintage that Pyongyang produces and that have limited applications on the modern battlefield.

Arms control expert Joshua Pollack said North Korea accounted for more than 40 percent of the approximately 1,200 ballistic missile systems supplied to the developing world between 1987 and 2009, mostly before the mid-1990s. But he said Pyongyang's client base has shrunk since then because of a ``sustained pressure campaign by the U.S. to get buyers of North Korea war materiel and technology to stop.''

``The main effect of sanctions and interdiction has been to put the heat on buyers, whenever the U.S. and its partners have some leverage over them,'' said Pollack, but he added that ``Iran and Syria don't care about what we think.''

North Korea is still believed to have missile cooperation with the two countries. But with the Syrian leadership fighting to survive a civil war, that market might also dry up. And Iran has now surpassed North Korea in missile development. It has already conducted successful space launches and, in addition to having adapted North Korean designs, is creating its own more sophisticated and more militarily useful medium-range missile, said Greg Thielmann of the Arms Control Association, a nongovernment group based in Washington.

For years, North Korea was a leading provider of missile systems, particularly to nations in the Middle East. Its first major client was Iran, during its long war with Iraq. They signed a missile development deal in 1985, and North Korea began mass-producing short-range Scuds, aided by Chinese know-how and using Soviet designs. It then graduated to medium-range missiles with a range of more than 1,000 kilometers (600 miles).

According to the International Institute for Strategic Studies, since the 1980s, North Korea has earned possibly hundreds of millions of dollars by selling at least several hundred short- and medium-range missiles to Egypt, Iran, Libya, Pakistan, Syria, the United Arab Emirates and Yemen.

The launch of the Unha-3 rocket was a handy showcase of North Korea's technical capabilities _ sending a satellite into space uses a similar technology as firing a long-range missile. The three-stage Unha-3 rocket, with a potential range of 8,000-10,000 kilometers (5,000-6,000 miles), succeeded after failures since 1998.

``The rocket launch dispels doubts about North Korea's missile capabilities and redeems the country's reputation among buyers,'' said Baek Seung-joo, a North Korea specialist at the South Korean state-run Korea Institute for Defense Analyses. ``The launch put an end to years of failure and embarrassment.''

However, few governments are likely to be in the market for such a long-range missile _ which North Korea remains years away from perfecting. 

Pyongyang is likely to continue to try selling shorter-range missiles and Soviet-vintage rockets and guns to customers in Africa, and likely Islamist groups such as Hezbollah and Hamas.

But the screw has tightened since North Korea's last nuclear test in 2009. Its weapons exports have been banned under U.N. Security Council resolutions. The sanctions call on member states to inspect and confiscate suspect cargoes, also including certain luxury goods, and report them to the world body.

The United States is also likely to seek tighter restrictions on the North after the latest launch, although it could face opposition from China, the North's only major ally.

Former British ambassador to North Korea, John Everard, who until recently served as coordinator of a U.N. panel of experts that reports on the implementation of the sanctions, said that while the North's arms exports haven't stopped, seizures have already caused it considerable financial and reputational damage, particularly when information about their customers becomes public.

But implementation has been patchy. The North goes to great lengths to circumvent controls, typically using neighboring China and other countries en route as transshipment points.

Tracking secret weapons shipments is difficult, but some trends emerge. Recent seizures indicate that North Korea is still shipping missile technology to Syria.

Last month, U.N. diplomats reported that 445 graphite cylinders from North Korea that can be used to produce ballistic missiles were seized in May from a Chinese freighter ship at the South Korean port of Busan on their way to Syria. In October 2007, propellant blocks that could be used to power Scud missile were seized from a ship heading to Syria, according to a report by the U.N. expert panel, released this June.

Iran and North Korea have shared missile technology, but it's less clear what the current state of their cooperation is, said a senior State Department official, speaking on condition of anonymity to discuss diplomatically sensitive, counter-proliferation issues.

In December 2009, Thailand intercepted a charter jet from Pyongyang carrying 35 tons of conventional weapons including surface-to-air missiles that Thai authorities reported were headed for Iran _ apparently for the use of a proxy militant group. The White House recently remarked on how Thailand had interdicted a North Korean weapons shipment bound for Hamas.

The U.S. official said North Korea is seeking buyers for its cheap weapons in Africa. In recent years, there have been seizures of shipments heading to countries including Eritrea, Republic of Congo and Burundi.

But combined with its shrinking markets in the Middle East, Myanmar's promise to end its military trade could badly hit North Korea's pocket book.

Myanmar's former ruling junta entered into commercial contracts with North Korea, most notably after a high-level military delegation visited Pyongyang in late 2008. According to the U.S., one agreement was for North Korea to assist Myanmar in building medium-range, liquid-fueled ballistic missiles.

In recent months, the United States has credited Myanmar with ``positive steps'' toward severing those military ties as the newly elected civilian government courts better relations and investment from the West.

But the U.S. official said Myanmar is not yet in compliance with U.N. Security Council resolutions, as North Korea still seeks to ship goods to Myanmar to fulfill the contracts. (AP)