MEXICO CITY - A US congressional report says about 70 percent of the guns seized by authorities in Mexico and submitted to a US gun-tracing program originated in the United States.

The figure has been polemical ever since a June 2009 US report said that 90 percent of the Mexican guns came from the United States. But the report released Monday includes guns seized through 2010.

The report by three US senators included figures provided by the Bureau of Alcohol, Tobacco, Firearms and Explosives.

The report 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 until 2004.