The growing tally of international weapon deals, which started to surge in 2006, is now provoking questions among some advocates of arms control and some members of Congress.

“Sure, this is a quick and easy way to cement alliances,” said William D. Hartung, an arms control specialist at the New America Foundation, a public policy institute. “But this is getting out of hand.”

Congress is notified before major arms sales deals are completed between foreign governments and the Pentagon. While lawmakers have the power to object formally and block any individual sale, they rarely use it.

Representative Howard L. Berman of California, chairman of the House Committee on Foreign Affairs, said he supported many of the individual weapons sales, like helping Iraq build the capacity to defend itself, but he worried that the sales blitz could have some negative effects. “This could turn into a spiraling arms race that in the end could decrease stability,” he said.

The United States has long been the top arms supplier to the world. In the past several years, however, the list of nations that rely on the United States as a primary source of major weapons systems has greatly expanded. Among the recent additions are Argentina, Azerbaijan, Brazil, Georgia, India, Iraq, Morocco and Pakistan, according to sales data through the end of last month provided by the Department of Defense. Cumulatively, these countries signed $870 million worth of arms deals with the United States from 2001 to 2004. For the past four fiscal years, that total has been $13.8 billion.

In many cases, these sales represent a cultural shift, as nations like Romania, Poland and Morocco, which have long relied on Russian-made MIG-17 fighter jets, are now buying new F-16s, built by Lockheed Martin.

At Lockheed Martin, one of the largest American military contractors, international sales last year brought in about $6.3 billion, or 15 percent of the company’s total sales, up from $4.8 billion in 2001. The foreign sales by Lockheed and other American military contractors are credited with helping keep alive some production lines, like those of the F-16 fighter jet and Boeing’s C-17 transport plane.