A U.S. Customs and Border Patrol (CBP) boat was fired upon from a Mexican riverbank, according to CBP.

“A #BorderPatrol Marine Unit patrolling near Fronton, TX reported they were fired upon from the Mexican riverbank. Agents saw 4 subjects who shot over 50 rounds at them. No one on board was injured, but the boat was hit. The incident is under investigation,” the law enforcement agency said in a Tweet.

The attack occurred early Friday morning.

CBP put out a press release about the incident, which said the agents were patrolling the Rio Grande River. The Rio Grande Valley, which is the southernmost tip of Texas, is infamous for illegal border crossings and cartel and gang-related violence.

The attack occurred during a time of gridlock in Washington, D.C. over border security. For the first two years of President Donald J. Trump’s term in office, establishment Republicans controlled both chambers of Congress, but were unable to work with the president on his flagship issue of border security.

Meanwhile, Democrats have careened in the totally opposite direction, calling for open borders, decriminalization of illegal border crossings, and the abolishment of U.S. Immigration and Customs Enforcement (ICE), which is responsible for protecting our borders, but also removing dangerous foreign-born terrorists and other criminals from U.S. soil. (RELATED: ICE Removes Iranian National Convicted of Illegal Arms Dealing)