U.S. Senate Judiciary Committee Chairman Lindsey Graham (R-S.C.) has raised warnings against Iran, saying its missile launched at Iraqi bases targeting American military is “an act of war” and that Tehran may be sanctioned on oil sales.

Iran fired 15 ballistic missiles into two Iraq bases housing U.S. troops on Tuesday in retaliation to an U.S. airstrike that killed Iranian general Qassem Soleimani last week.

Fox News citing a U.S. military spokesman said 10 missiles hit Al-Assad Air Base, one hit a military base in Erbil and four other missiles failed their targets. The attacks unfolded in two waves, each about an hour apart.

In an initial reaction, President Donald Trump tweeted, “All is well! Missiles launched from Iran at two military bases located in Iraq. Assessment of casualties & damages taking place now. So far, so good! We have the most powerful and well equipped military anywhere in the world, by far!”

The president said he would make a statement on Wednesday morning, Jan. 8.

In an interview with Fox News late Tuesday, Sen. Graham called Iran’s decision “an act of war… by any reasonable definition.”

Graham said President Trump has all the authority he needs to respond under Article II, and that he should try to “restore deterrence.”

Graham said President Trump should focus on three areas—Iran’s ballistic missile program, their support for terrorist groups, and a nuclear deal that does not allow Iran to develop a nuclear weapon.

“His response tonight is to deal with those three buckets. How do we get the regime to change their behavior,” Graham said. “The price to be paid by the Iranians had to go up before they will change.”

Graham, an ally of President Trump, also warned Iran over potential economic sanctions, saying its fate is in its own hands in terms of economic viability.

“You continue this … crap, you’re going to wake up one day out of the oil business,” Graham said.

Includes reporting from The Hill