The decision to bolster U.S. military presence in the Persian Gulf was made after a Hezbollah proxy group received instructions to kill and kidnap U.S. soldiers, according to Rep. Michael McCaul of Texas.

“To the extent I can discuss it, it was human intelligence,” McCaul told USA Today of the threat that motivated the U.S. to beef up its presence in the Persian Gulf.

According to McCaul, U.S. intelligence officials discovered the leader of Iran’s Quds Force told Iran’s proxy militias that, “We are getting ready to have a proxy war and target Americans.” Hezbollah, an Iranian-backed terrorist organization, also received the same instructions.

“One of the Hezbollah cells is known for its kidnapping and killing operations, and their directive was to go in and kill and kidnap American soldiers,” the ranking members of the House Foreign Affairs Committee said.

The Trump administration has recently sent the USS Abraham Lincoln, B-52 bombers, and a Patriot antimissile battery to the Middle East to respond to “troubling and escalatory threats” from Iran.

But some lawmakers have cast doubt that threats from Iran have escalated and have expressed concern about a military confrontation with Iran. For example, Rep. John Garamendi, D-Calif., warned that U.S. could head toward a Gulf of Tonkin-type incident, the naval attacks that prompted the U.S. to become involved in the Vietnam War.

“What I heard is information that indicates that there is a threat, but it's the same threat that was there six months ago, a year ago, and, in fact, is less because ISIS is defeated,” Garamendi said in an interview with CNN this week. “Yes, there are concerns in Iraq. Do we need an aircraft carrier to deal with those? Do we need B-52 bombers? Or do we have the drumbeat of war here? Are we headed for a Gulf of Tonkin situation? I believe we may very well be in that situation.”