By Michael O'Boyle and Patricia Zengerle
CULIACAN, Mexico/WASHINGTON (Reuters) - Efforts to combat illegal gunrunning from the United States to Mexico has stumbled in recent years, hampered by less cooperation between U.S. and Mexican officials, according to a report from a U.S. federal watchdog agency obtained by Reuters.
The draft report from the Government Accountability Office (GAO), to be released after the latest arrest of Mexican drug lord Joaquin "El Chapo" Guzman, also criticized U.S. law enforcement agencies for not ensuring they are effectively working together to fight arms smuggling by Mexico's ruthless drug cartels.
Squabbling between U.S. authorities and Mexico over Guzman has put an intense focus on the issue of cooperation. Mexico, which refused to extradite him to the United States when he was arrested in 2014, was formally starting extradition proceedings against Guzman after his latest capture.
"Efforts to stem firearms trafficking between the United States and Mexico were scaled back as the administration of Mexican President Enrique Pena Nieto reconsidered bilateral law enforcement cooperation," the report said, citing U.S. and Mexican officials.
Mexico tightly restricts gun sales but the flow south of U.S. weapons helped fuel battles between drug gangs and security forces that have killed more than 100,000 people since 2007.
Experts say operations to stem the flow of guns south have had little success, pointing to the botched "Fast and Furious" sting in which U.S. agents lost track of guns allowed to enter Mexico between 2009 and 2011.
The GAO report was commissioned by U.S. Representative Eliot Engel, a Democrat from New York, as a follow-up to a similar GAO study in 2009. The agency is expected to release it as soon as later on Monday.
Pena Nieto dialed back cooperation with U.S. authorities after taking office in late 2012. U.S.-Mexico law enforcement ties, long undermined by mutual distrust, had improved under Pena Nieto's predecessor, Felipe Calderon.
Upon taking office, Pena Nieto's administration balked at the extent of U.S. involvement in Calderon's war against drug gangs and Pena Nieto's team limited U.S. law enforcement access.
CONCERNS ABOUT CORRUPTION
The report said collaboration between the two countries has improved in the last year, but cited concerns about corruption among Mexican authorities. Pena Nieto replaced his attorney general last year with an official more open to working with the U.S. government than her predecessor.
Of the nearly 105,000 guns seized by Mexican authorities and submitted for tracing from 2009 to 2014, 70 percent came from the United States, according to data from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) cited in the study.
Another 17 percent were traced to other countries, while 13 percent could not be tracked, possibly due to the failure of U.S. gun shops that closed down to turn over records.
However, only two-thirds of the seized guns were submitted for tracing, according to Mexican data cited in the report. As a result, "it is not possible to develop data to track trends on firearms seized," the report said.
Available data showed a drop since 2011 in the number of weapons confiscated by security forces in Mexico and traced to the United States.
However, the GAO said Pena Nieto's government restricted access to the ATF's eTrace software.
"Some U.S. officials based in Mexico ... noted that limited access to Spanish language eTrace diminished tracing of total firearms seized by Mexican authorities," the report said.
The report also said the U.S. Immigration and Customs Enforcement (ICE) and ATF have failed to ensure their agents are effectively cooperating on arms trafficking investigations.
The GAO said it found persistent gaps in information-sharing between ATF and ICE, and confusion about their roles even after the 2009 GAO report pushed them to improve teamwork.
Mexican lawmakers and experts claimed lax U.S. gun control is the main reason for the ease with which traffickers buy and move guns. They also blamed corruption among Mexican customs agents.
"The fight against arms trafficking has been a failure," said Raul Benitez, a security expert at the National Autonomous University in Mexico.
(Reporting by Michael O'Boyle in Culiacan, Mexico and Patricia Zengerle in Washington Editing by Jeffrey Benkoe)