A gunman was killed after opening fire at a US Border Patrol facility in Texas.

A 27-year-old man was fatally shot after entering the Rio Grande Valley Border Patrol building near McAllen International Airport shortly before 6am on Monday, authorities said.

He was reportedly armed with a rifle and wearing tactical gear, McAllen police chief Victor Rodriguez told reporters on Monday morning.

Fox News reported the gunman had “ambushed” border patrol agents.

No federal agents were injured, although one McAllen police officer was struck, either by shrapnel or a bullet, and is currently in a stable condition.