A U.S. Border Patrol agent chasing illegal immigrants on Friday fired several shots at an armed man who later identified himself as a militia member, heightening concerns about an influx of uninvited volunteers who have flocked to the Southwest border in recent weeks.

Friday’s shooting followed another incident this month in which agents mistook seven militia members as part of a law-enforcement tactical team after they appeared out of the dark dressed in camouflage and carrying rifles to help capture illegal immigrants in Texas.

A U.S. Border Patrol agent walks on a road by the U.S.-Mexican border at the Rio Grande River, near McAllen,Tex., on Aug. 19. (Michael Reynolds/European Pressphoto Agency)

No one was injured in either of the encounters, but the Border Patrol has advised militia members to “properly and promptly identify” themselves whenever they come across authorities, and the agency sent out an “issue paper” to warn other agents about such situations, according to reports from the Los Angeles Times and the Associated Press.

The incidents have prompted border officials to consider talks protocols for dealing with the militias, the reports said.

In Friday’s encounter, the agent fired several rounds before the militia member dropped his weapon, Customs and Border Protection spokesman Omar Zamora told the Times.

It is unclear whether the armed individual, whose identity has not been released, will face criminal charges, but the Cameron County Sheriff’s Office is investigating the matter, the Times said. Officials have said the man was on private property at the time of the shooting.

Militia members have rushed to the Texas-Mexico border in response to a rapid influx of Central American immigrants who entered the United States in that region. U.S. authorities this year have apprehended about 60,000 immigrants, many of them unaccompanied children.

The wave of immigrants arriving from Central America has slowed since authorities began sending the individuals home,according to the Obama administration. But that hasn’t stopped militias such as the Oathkeepers, the Minutemen, the Patriots, and the Three Percenters Club from sending armed members to the border.

CBP said in a statement Tuesday that it does not endorse or support the militia activities, saying taking matters into their own hands “could have disastrous personal and public safety consequences.”

The agency noted that its border agents undergo 17 weeks of specialized training to qualify for their work.