A senior lawmaker alleges that Ukraine sold nuclear-capable cruise missiles to Iran and China in violation of international nonproliferation treaties and is demanding the new government launch a full investigation.

The allegations were made in a letter — made available to The Associated Press on Tuesday — by lawmaker Hrihory Omelchenko (search) and addressed to President Viktor Yushchenko (search), a reformist who took office last week.

Yushchenko, who takes over from Leonid Kuchma (search), has promised a thorough investigation of corruption and misdeeds that allegedly flourished during his predecessor's 10 years as president.

Kuchma allegedly sanctioned the sale of sophisticated radar systems to Iraq in 2002, contravening U.N. sanctions.

In the letter, Omelchenko said an investigation launched last summer "proved that some 20 air-launched Kh-55 (search) and Kh-55M (search) cruise missiles with nuclear capability were exported to third countries" in contravention of international treaties.

"Six missiles destined for Russia ended up in Iran ... six missiles destined for Russia ended up in China" the letter said. It said the exports occurred during 1999 to 2001.

Omelchenko is an ally of Yulia Tymoshenko (search), who has been nominated as Ukraine's next prime minister.

Vyacheslav Astapov, a spokesman for Ukraine's Prosecutor-General, said the office began an investigation into the alleged sales last summer and "this year we received new information."

Astapov also said a top-ranking Iranian diplomat in Ukraine met with Prosecutor-General Svyatoslav Piskun, but he did not elaborate.

Iranian diplomats in Kiev were not available for comment.

Omelchenko also claimed that businessmen from several enterprises — including state-run weapons exporter Ukrspetseksport (search) and its daughter companies — companies in the United States, Cyprus and Iran and individuals from the Ukrainian security service shared hefty profits from several illicit defense deals that included sales of radar equipment to Eritrea.

Officials from the Ukrspetseksport and the Ukrainian Security Service were unavailable for comment.

American diplomats in Kiev were "aware of the reports" on illicit missile sales and took them "very seriously," a U.S. embassy spokesman said.

"Nonproliferation remains a key pillar in the global war on terror in which Ukraine is a close partner," the spokesman said on condition of anonymity.

The Kh-55, known in the West as the AS-15, has a range of 3,000 kilometers (1,860 miles) and is designed to carry a 200-kiloton nuclear warhead. It is designed for use on Russian-made Tupolev long-range bombers.

Iran's air force does not operate such planes, but some military analysts have suggested that its Soviet-built Su-24 strike aircraft could be adapted to use the Kh-55.

China operates about 120 H-6 medium-range bombers.

In the early 1990s, Ukraine renounced the nuclear armaments it inherited in the breakup of the Soviet Union and said it shipped all of its nuclear warheads to Russia for decommissioning under U.S. control.

The country remains a sizable producer of weapons, including missiles, aircraft and tanks. Exports are largely to other former Soviet republics, Asia and Africa.

Last year Ukrainian police arrested four men from Greece, Pakistan and Iraq on suspicion of attempted illegal weapons trade worth more than $800 million for an unspecified force fighting in Iraq.

Last March, former Defense Minister Yevhen Marchuk (search) warned that several hundred Soviet-built SA-2 surface-to-air missiles are unaccounted for.

Defense officials later claimed that these missiles from arsenals in former Warsaw Pact member countries had been brought to Ukraine for decommissioning and were lost due to "accounting problems" and "the absence of records."