How North Korea earns money from arms sales?

Following North Korea's May 25 nuclear test, the U.N. Security Council imposed new sanctions to halt the North's missiles sales, a vital source of cash for the destitute state.

Here are some questions and answers about the North's suspected proliferation activities:

HOW MUCH DOES NORTH KOREA MAKE FROM ARMS SALES?

The U.S.-based Institute for Foreign Policy Analysis estimates that North Korea, with an annual GDP others estimate of about $17 billion, earns some $1.5 billion a year from missile sales. Other studies said the figure may be in the hundreds of millions of dollars, with prior U.N. sanctions and other restrictions cutting into exports.

The United States suspects the North has also sold nuclear know-how, but there are no figures readily available on income.

WHO ARE THE CUSTOMERS?

Since the 1980s North Korea has sold missile systems to Iran, Pakistan, Egypt, Libya, Syria and Yemen, the International Crisis Group said in a report last month. Experts said these include the North's variants of the Scud missile and its mid-range Rodong ballistic missile.

The ICG report also said there is strong evidence that North Korea was cooperating with Syria in an attempt to build a reactor that could be used in a plutonium-based weapons programme. The suspected Syrian facility was destroyed by the Israeli air force about two years ago.

WILL U.N. SANCTIONS WORK?