WASHINGTON - The Federal Bureau of Investigation (FBI) is investigating former counterterrorism official Joe Kent, who resigned in protest over the Iran war, US media reported Wednesday.

The bureau's investigation was underway before Kent resigned Tuesday as director of the National Counterterrorism Center, said NewsNation, citing a source.

"Joe Kent is under FBI investigation for allegedly leaking classified information, three sources tell me. I'm told the investigation pre-dates his departure," Shelby Talcott, White House correspondent for news website Semafor, wrote in a post on X.

Tuesday, Kent announced on X that he has decided to resign from his position as he "cannot in good conscience support the ongoing war with Iran."

"Iran posed no imminent threat to our nation, and it is clear that we started this war due to pressure from Israel and its powerful American lobby," he wrote in the post.

Kent noted that early in this administration, high-ranking Israeli officials and influential members of the American media deployed a misinformation campaign that wholly undermined President Donald Trump's America First platform and sowed pro-war sentiments to encourage a war with Iran.

Analysts say the resignation of a top US counterterrorism official signals mounting pressure on the Trump administration over the Iran war, amid intensifying criticism from Democratic lawmakers, business leaders, and even segments of his own support base.

Recent polls show that a significant portion of the Make America Great Again (MAGA) supporters continue to back Trump's military actions against Iran. Meanwhile, several key MAGA opinion leaders have publicly voiced their opposition, including Trump's former chief strategist Steve Bannon.