WASHINGTON — The United States has attributed the drone attack that killed three U.S. service members in Jordan to the Islamic Resistance in Iraq, an umbrella group of Iran-backed militias that includes the militant group Kataib Hezbollah.

National Security Council spokesman John Kirby said Wednesday the U.S. believes the attack was planned, resourced and facilitated by the group.

The Sunday drone attack on a military base in Jordan killed the three troops and injured at least 40 others. Kirby says President Joe Biden will continue to weigh response options to the attack but “the first thing you see won’t be the last thing.”