WASHINGTON: The US Air Force said on Thursday (Jul 2) it would investigate a uniformed officer who called for the impeachment of US President Donald Trump and Vice President JD Vance during a protest event on the steps of the Capitol.

The active-duty officer, Major Jason Watson, denounced Trump and Vance on Wednesday for actions including going to war with Iran without congressional authorisation, according to a video of the protest event posted online.

In one part of the video, the US Capitol Police can be seen detaining Watson, who held a protest sign calling for the impeachment, conviction and removal of Trump and Vance.

Without mentioning Watson by name, the office of Air Force Secretary Troy Meink acknowledged reports about an Air Force officer protesting at the Capitol and said in a statement that an investigation "will proceed unimpeded."

"The Department takes allegations of misconduct seriously, including any that might undermine the nonpartisan nature of our military," it said in a post on X.

Laws governing US military service members place restrictions on their political activities, particularly while in uniform. Article 88 of the Uniform Code of Military Justice also prohibits officers from using "contemptuous words against the President, the Vice President, Congress" and other US representatives.

Watson suggested he was aware of the risks in his remarks, saying: "What matters far more than who I am is what I have to say and the price I'm willing to pay to say it."

Reuters was not able to reach Watson for comment.