MOSCOW, Aug. 15  A proposed contract between Russia and Venezuela that could transfer thousands of sniper rifles to Venezuela has raised concerns in the United States about the potential use or regional distribution of the weapons by the socialist-inspired government of President Hugo Chávez.

The rifles are the latest variant of the Dragunov, a long-barreled, semiautomatic design with a telescopic sight. It is derived in part from the much more widely circulated Kalashnikov assault rifle.

First manufactured in 1963 for use by militaries and intelligence agencies in the Soviet Union and Warsaw Pact nations, the Dragunov and its clones have become among the most lethal and effective weapons against American troops and their allies in Iraq.

Venezuela is negotiating a contract with Rosoboronexport, the Kremlin-controlled arms export agency, to purchase about 5,000 modernized Dragunov rifles, according to officials at Izhmash, the rifle’s manufacturer.