(CNN) -- Four Humvees carrying 33 Mexican soldiers crossed the border into the United States, and officials on both sides say it was a harmless mistake.
The convoy of military vehicles crossed the recently-opened Donna-Rio Bravo International Bridge, which links the two cities of the same names in Texas and Mexico.
The incident happened about 1:30 p.m. Tuesday, Customs and Border Protection spokesman Rick Pauza said.
The soldiers "just said they inadvertently crossed onto the U.S. side," he said.
The military men were processed at the port of entry before being allowed to cross back, he said.
For its part, the Mexican military said that while patrolling the border, they accidentally got on the international bridge and had no choice but to enter the American side because that is where the turnaround is located.
"Everything was fine. There was no resistance and no other issues there," Pauza said.
Any time the Mexican military crosses the international border, it draws attention, however, as previous incursions have been recorded.
In 2008, seven members of the Mexican military were found inside the United States, telling border agents that they became lost and accidentally entered the country.
In 2006, a group of soldiers -- or men dressed as soldiers, as Mexican officials said -- were recorded accompanying suspected drug smugglers who became stuck in the Rio Grande.
CNN's Simon Hernandez-Arthur contributed to this report.
