Mexican authorities have recovered 68,000 guns in the past five years that have been traced back to the United States, the federal government said Thursday.

The flood of weapons underscores complaints from Mexico that the United States is responsible for arming the drug cartels plaguing America’s southern neighbor. More than 47,000 people in Mexico have been killed in six years of violence between warring cartels.

The Bureau of Alcohol, Tobacco, Firearms and Explosives, in releasing its latest data covering 2007 through 2011, said that many of the guns seized in Mexico and submitted to the ATF for tracing were recovered at the scene of cartel shootings while others were seized in raids on illegal arms caches. All the recovered weapons were suspected of being used in crimes in Mexico.

At a North American summit in Washington on April 2, Mexican President Felipe Calderon said the U.S. government has not done enough to stop the flow of assault weapons and other guns.

Calderon credited President Obama with trying to reduce the gun traffic, but he said that Obama faces political resistance.

There is Republican opposition in Congress and broad opposition from Republicans and gun-rights advocates elsewhere to a new assault weapons ban or other curbs on gun sales. The Obama administration says it is working to tighten inspections of border checkpoints in the absence of an assault-rifle ban that expired before Obama took office.

For more than a year, the ATF has been reeling from accusations that some of its agents in Arizona were ordered by superiors to step aside rather than intercept weapons headed for Mexico. The Justice Department’s inspector general and Congress have been looking into the incident, known as Operation Fast and Furious.

Gun-control legislation hasn’t been a subject of the Republican-led probe of Fast and Furious by the House Oversight and Government Reform Committee.

The number of ATF-traced firearms manufactured in or imported into the United States and later recovered in Mexico rose from 11,842 in 2007 to 14,504 in 2011, the agency said. The figures for U.S.-sourced firearms were 21,035 in 2008, 14,376 in 2009 and 6,404 in 2010.

The number of rifles included in those totals rose from 4,885 in 2007 to 8,804 last year.

Mexico has provided the ATF with information on 99,691 guns. The ATF determined that the source for 68,161 of the weapons was the United States — 68 percent of the total. The agency couldn’t determine a U.S. source or was unable to trace the request to a country of origin for the other guns. The 68 percent figure is down from estimates of 90 percent in years past when Mexico was sharing less information with the United States.

“Letting guns walk” out of shops in the hands of suspected straw purchasers was an Operation Fast and Furious tactic at the ATF in Phoenix. The plan was to track the guns to major weapons traffickers and drug cartels to make criminal cases against smuggling kingpins. But the effort was faulty, and many weapons wound up at crime scenes in Mexico and the United States. Two of the guns spotted at one point during Fast and Furious were later discovered at the scene of the killing of U.S. border agent Brian Terry.

Before Fast and Furious, the ATF in Arizona had tried the gun-walking tactic in three investigations during the George W. Bush administration, with tracking problems and limited success.

Under the Obama administration, the ATF has undergone a management shake-up and ­Attorney General Eric H. Holder Jr. has called Fast and Furious a flawed operation.

Ineligible to run for reelection, Calderon made a government crackdown on warring drug cartels the hallmark of his six-year term. His center-right party’s prospects in the July 1 presidential election have declined in the face of a perception that the crackdown failed.

U.S. gun store owners in southwestern border states sued to overturn an Obama administration requirement that they report to the ATF when customers buy multiple high-powered rifles within a five-day period. A federal court upheld the requirement.

— Associated Press