A man with a rifle and tactical gear was shot dead by police after he opened fire at a Border Patrol facility in Texas on Monday morning, the Department of Homeland Security (DHS) has said.

Two officers and a border patrol employee were injured in the attack, including one who was shot in the knee. All three were sent to hospital for treatment, officials said.

The shooting occurred at the entrance of a US Border Patrol sector annex in McAllen, Texas, near the US-Mexico border.

McAllen police have identified the suspect as 27-year-old Ryan Lewis Mosqueda. He has no known criminal record and has an address in Michigan. Police said a motive has not yet been determined.

The shooting occurred around 06:00 local time (11:00 GMT), McAllen Police Chief Victor Rodriguez said.

The suspect fired "many dozens of rounds" towards the border patrol building and towards agents inside the building, Rodriguez said. Agents then fired back and killed the suspect.

Rodriguez said the suspect arrived in Texas with a Michigan-tagged vehicle, and was reported missing a few hours before the shooting from an address in Weslaco, Texas - a town around 18 miles (28km) east of McAllen.

Police also found other weaponry and ammunition inside the vehicle.

Images from the scene show the driver's side door of the vehicle was spray-painted with "Cordis Die", a latin phrase meaning "Day of the Heart".

In the Call of Duty: Black Ops II video game, Cordis Die is a revolutionary movement that aims to cripple capitalist governments, according to gamer websites.

Interviewed by Fox News on Monday evening, US border tsar Tom Homan linked the phrase on the suspect's car to the Call of Duty game.

Homan also sought to blame rhetoric from Democratic lawmakers for the attack, referring to Representative Pramila Jayapal calling ICE "a terrorist force" and House minority leader Hakeem Jeffries likening the immigration agency to the Gestapo.

"Unless we stop hateful rhetoric against ICE, border patrol, comparing them to Nazis, there's going to be more loss of life," he said.

"They're simply enforcing law that Congress enacted."

One of the officers injured in the exchange is a 10-year veteran with the McAllen Police Department. He was shot in the knee and is recovering in hospital.

No federal officers were shot or wounded, police said.

The building where the shooting occurred is located near the McAllen airport, prompting traffic to be temporarily closed.

The FBI has now taken over the investigation, Rodriguez said, adding that police have no reason to believe there are more threats to the community. (BBC)