BANGKOK, Thailand — A Russian arms dealer accused of breaking U.N. arms embargoes by supplying weapons to African war zones was arrested today in Bangkok, Thai police said.

The arms dealer, Viktor Bout, was arrested in the heart of the capital city on a warrant issued by a Thai court, a police lieutenant general and head of the Crime Suppression Bureau, Pongpat Chayapan, said. The warrant stemmed from an earlier one issued by the U.S. Drug Enforcement Administration, he said.

An American Embassy spokesman “congratulated” Thai police for the arrest but could not provide details about the role American officials played in it. Details of the charges against Mr. Bout were also not immediately available.

Mr. Bout allegedly has been trafficking weapons to Central and West Africa since the early 1990s. U.N. reports say he set up a network of more than 50 aircraft around the world and trade experts have said the illicit diamond trade was likely one source of funds for his smuggled arms shipments.

Although Mr. Bout has been investigated by police in several countries, he has never been prosecuted for arms dealing.

A 2005 report by Amnesty International, a Britain-based human rights watchdog, alleged Mr. Bout was “the most prominent foreign businessman” involved in trafficking arms to U.N.-embargoed destinations from Bulgaria, Slovakia, Ukraine, Kyrgyzstan, and other countries.

The report also implicated Mr. Bout in transferring “very large quantities of arms” from Ukraine that were delivered to Uganda via Tanzania aboard a Greek-registered cargo ship.

In 2003, the United Nations imposed an arms embargo on the provinces of North and South Kivu and the Ituri regions of eastern Congo, and also on groups that were not a part of the 2003 peace agreement for the region.