About 70 percent of the guns seized in Mexico and submitted to a U.S. gun-tracing program came from the United States, according to a report released by three U.S. senators Monday.

Of the 29,284 firearms recovered by authorities in Mexico in 2009 and 2010, 20,504 came from the United States, according to figures provided to the senators by the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Most of those weapons _ 15,131 _ were U.S. made, while another 5,373 were of foreign manufacture but had moved through the United States into Mexico.

The ATF said the remainder of the weapons total _ 8,780 arms _ were of "undetermined origin due to insufficient information provided."

The figure of the number of guns arriving in Mexico from north of the border has been polemical ever since a June 2009 U.S. report covering earlier years said that 87 percent of guns seized in Mexico came from the United States.

While the report did not specify why the percentage had changed, the most recent figures appear to included more gun-trace reports, as the reporting program in Mexico became easier to use.

Evidence that U.S. weapons trafficking has been fueling a bloody drug war that has cost more than 35,000 lives in Mexico since late 2006 has angered many Mexicans.

On Saturday, in a speech to the Mexican-American community in San Jose, California, President Felipe Calderon lashed out at the U.S. weapons industry.

"I accuse the U.S. weapons industry of (responsibility for) the deaths of thousands of people that are occurring in Mexico," Calderon said. "It is for profit, for the profits that it makes for the weapons industry."

The report, issued by Sen. Dianne Feinstein of California and two other senators, recommended background checks for sales at gun shows, a ban on the import of nonsporting weapons and the reinstatement of the assault weapons ban in force in the United States until 2004.

Calderon endorsed calls for reinstating the ban on domestic sales of assault rifles, saying its expiration in 2004 may have played a roll in the increase of drug violence in Mexico.

"You can clearly see how the violence began to grow in 2005, and of course it has gone on an upward spiral in the last six years," Calderon said.