Sen. Chris Murphy, D.-Conn., said in a statement late Sunday that he hopes to be briefed on the President Biden-approved airstrikes against three facilities near the Iraq-Syria border that were conducted without the approval of congress.

Murphy, who also voiced concern about the February strikes in the region, said the president has the ability to defend forces abroad, but his concern is that "the pace of activity directed at U.S forces and the repeated retaliatory strikes against Iranian proxy forces are starting to look like what would qualify as a pattern of hostilities under the War Powers Act."

His spokesman did not immediately respond to a late call from Fox News.

Pentagon Press Secretary John Kirby said the militias were using the facilities to launch unmanned aerial vehicle attacks against U.S. troops in Iraq.

Kirby said the U.S. military targeted three operational and weapons storage facilities — two in Syria and one in Iraq. He described the airstrikes as "defensive," saying they were launched in response to the attacks by Iran-backed groups.

A U.S. defense official with knowledge of the strikes told Fox News that US Air Force F-15s and F-16s were used in the operation. The strikes took place at approximately 6 p.m. Eastern Time, or 1 a.m. local time.

Biden's first known military action in February, when an airstrike targeted a compound in Syria operated by Kait’ib Hezbollah and Kait’ib Sayyid al Shuhada.

Murphy, the chairman of the Senate Foreign Relations Subcommittee on Near East, South Asia, Central Asia, and Counterterrorism, also called the February strikes "unacceptable."

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He told NPR at the time, "What we've said through the War Powers Act is that the president has the ability to strike without congressional authorization if he's trying to prevent an imminent threat against U.S. troops. But he doesn't, under the War Powers Act, have the ability to take a retaliatory strike without coming to Congress first. If it's not an emergency, then the Constitution generally says you've got to get signoff from Congress."

Fox News' Lucas Y. Tomlinson and the Associated Press contributed to this report