A watchdog group says Mexican military or other Mexican government agents have made at least 29 incursions into the U.S. during a 12-month period.
The conservative U.S.-based public interest group Judicial Watch says the U.S. border patrol confirmed those incursions during fiscal year 2006.
It says in 17 of those incidents, the Mexican officials were armed.
Judicial Watch got the information through a request under the Freedom of Information Act.
It includes a description of a confrontation in January of 2006 between Texas officials and several armed men in military uniforms who were seen in a military Humvee near Fort Hancock, Texas. No shots were fired, and the suspects fled back into Mexico.
Mexican authorities deny that any of their soldiers were involved.
Judicial Watch says the documents show a "dangerous and chaotic situation at the Mexican border."
U.S. officials have also been accused of incursions into Mexico. In November of 2006, U.S. Border Patrol agents chasing suspected drug traffickers in Texas allegedly crossed into Mexico and had a brief standoff with Mexican police officers.