A group of military veterans gathered in the office of Arizona Sen. John McCain on Thursday to demand that he lead a vote against confirming Rex Tillerson as secretary of state.

About 10 veterans came to McCain's senate office and stood in military formation. The protest was live-streamed on Facebook.

“We have a real concern about an oil executive becoming secretary of state," said Matt Howard, a Marine Corps veteran of the Iraq War. "We know that this has been an industry and a person that has used the military to subsidize his own ability to make profit.”

Howard also added that Tillerson had put national security at risk, a likely allusion to Exxon's business dealings with Iran, Syria, and Sudan while he served as CEO.

"This is clearly an irresponsible pick for secretary of state," Howard said. "And we really want to see Sen. McCain make the right decision and reject his confirmation as secretary of state and encourage other members to reject him."

On the livestream, McCain staffers repeatedly tried to stop them from filming, citing senate rules against the practice. One of the veterans said the Capitol police had been called. Some of those present were hopeful that McCain — a fellow veteran of the Vietnam War — would eventually meet with them.

McCain's office did not immediately respond to a request for comment.

The confirmation vote for Tillerson is slated for Monday.