Democratic Sen. Mark Kelly on Monday insisted he would not be silenced by President Donald Trump or Defense Secretary Pete Hegseth, even as the Pentagon launches a “thorough review” into what it described as “serious allegations of misconduct” involving the senator.

“I will not be intimidated by this president,” Kelly said during a Monday afternoon news conference. “I am not going to be silenced by this president or the people around him because I’ve given too much in service to this country to back down to this guy.”

The Pentagon review was announced last week, following a video posted by Kelly and several other Democrats in which they stated that U.S. service members are obligated to refuse unlawful orders.

Kelly sharply criticized Hegseth, calling him “unqualified for this position” and urging him to testify about a controversial U.S. operation in the Caribbean Sea. That incident involved airstrikes on a boat suspected of smuggling drugs in September. Two survivors from an initial strike were allegedly killed in subsequent strikes authorized afterward.

The White House confirmed that more than one strike occurred on the vessel. A person familiar with the incident told ABC News that while some passengers survived the first strike, those survivors were killed in follow-up strikes.