The U.S. military carried out retaliatory precision air strikes on Monday in Iraq after a one-way drone attack earlier in the day by Iran-aligned militants that left one U.S. service member in critical condition and wounded two other U.S. personnel, officials said.

At President Joe Biden's direction, the U.S. military carried out the strikes at 1:45 GMT, likely killing "a number of Kataib Hezbollah militants" and destroying multiple facilities used by the group.

"These strikes are intended to hold accountable those elements directly responsible for attacks on coalition forces in Iraq and Syria and degrade their ability to continue attacks. We will always protect our forces," said General Michael Erik Kurilla, head of U.S. Central Command, in a statement.

A U.S. base in Iraq's Erbil that houses U.S. forces came under attack from a one-way drone earlier on Monday, leading to the U.S. casualties.

The Pentagon did not disclose details about the identity of the service member who was critically wounded or offer more details on the injuries sustained in the attack.

"My prayers are with the brave Americans who were injured," U.S. Defense Secretary Lloyd Austin said in a statement.

The White House National Security Council said Biden was briefed on the attack on Monday morning and ordered the Pentagon to prepare response options against those responsible.

"The President places no higher priority than the protection of American personnel serving in harm’s way. The United States will act at a time and in a manner of our choosing should these attacks continue," NSC spokesperson Adrienne Watson said.

Monday's military attack and U.S. retaliation is the latest back-and-forth since a surge in violence began in mid-October, when Iran-aligned militias started targeting U.S. assets in Iraq and Syria over Washington's backing of Israel in its war against Hamas in Gaza.

Iran vows Israel ‘will pay’ for death of military leader.

Iranian President Ebrahim Raisi vowed retribution after Israel reportedly killed a high-ranking general in Iran’s Islamic Revolutionary Guard Corps in Syria on Monday.

In a statement, Raisi said that Israel “will certainly pay for this crime,” The Times of Israel (TOI) reported.

“Without a doubt, this action is another sign of frustration, helplessness, and incapacity of the usurping Zionist regime in the region,” Raisi said in the statement.

Brig. Gen. Razi Mousavi was reportedly killed in an Israeli airstrike in the Damascus suburb of Sayida Zeinab, the Iranian Tasnim news agency reported Monday.

Israel Defense Forces (IDF) spokesperson Rear Adm. Daniel Hagari declined to comment on the alleged airstrike at a Monday press conference, TOI reported.

The TOI also reported that Iran’s foreign minister, Hossein Amir-Abdollahian, said on X, formerly Twitter, that “Tel Aviv faces a tough countdown,” and said Mousavi “fought bravely for many years… to ensure the security of Iran and the region.”

The strike comes as tensions on Israel’s northern border remain high, between Israel and Hezbollah.

Mousavi was reportedly a close associate of Iranian Gen. Qassem Soleimani, who was killed in a U.S. drone strike in 2020. He was reportedly responsible for coordinating the military alliance between Iran and Syria and believed to be involved in supplying arms to Hezbollah, TOI reported.

Tensions between Iran and Israel have only risen higher in the last two months as Israel has bombarded Gaza in response to the Oct. 7 attack on Israel by the group, which is designated by the U.S. government as a terrorist organization.

Fears that a wider war could break out have been a recurrent amid the Gaza war, as Hezbollah has fired rockets into northern Israel.

Iran-backed Houthi rebels in Yemen have also disrupted shipping through the Red Sea in another sign of the risks of a widening war.