WASHINGTON (AP) — The U.S. and U.K. on Thursday imposed a new round of sanctions on Iran as concern grows that Tehran’s unprecedented attack on Israel could fuel a wider war in the Middle East.

Treasury’s Office of Foreign Assets Control targeted 16 people and two entities in Iran that produce engines that power the drones used in the April 13 attack on Israel. OFAC also sanctioned five firms involved in steel production and three subsidiaries of Iranian automaker Bahman Group — which is accused of materially supporting Iran’s military and other sanctioned groups. A representative from Bahman was not immediately available for comment.

Additionally, the U.K. is targeting several Iranian military branches and individuals involved in Iran’s drone and ballistic missile industries.

President Joe Biden said in a statement that he had directed U.S. Treasury “to continue to impose sanctions that further degrade Iran’s military industries.” “Let it be clear to all those who enable or support Iran’s attacks,” he said, “we will not hesitate to take all necessary action to hold you accountable.”

U.K. Prime Minister Rishi Sunak said in a statement that the sanctions “will further limit Iran’s ability to destabilize the region.”

In addition to Treasury’s sanctions, the U.S. Commerce Department is imposing new controls to restrict Iran’s access to basic commercial grade microelectronics, which apply to items manufactured outside the U.S. that are produced using U.S. technology.

The actions come after U.S. officials earlier this week warned that they were readying new sanctions in response to Iran’s activity in the region and to prevent future attacks. Lawmakers on Capitol Hill also have been quickly pushing forward legislation that would financially punish the Islamic Republic and its leaders.

Iran’s attack on Israel early Sunday came in response to what it says was an Israeli strike on Iran’s consulate in Syria earlier this month. Israel’s military chief said Monday that his country will respond to the Iranian attack, while world leaders caution against retaliation, trying to avoid a spiral of violence.

European Union leaders also vowed on Wednesday to ramp up sanctions on Iran, targeting its drone and missile deliveries to proxies in Gaza, Yemen and Lebanon.

EU foreign policy chief Josep Borrell said the existing EU sanctions regime would be strengthened and expanded to punish Tehran and help prevent future attacks on Israel. At the same time, he said, Israel needed to exercise restraint.

“I don’t want to exaggerate, but we are on the edge of a war, a regional war in the Middle East, which will be sending shockwaves to the rest of the world, and in particular to Europe,” he warned. “So stop it.”

The U.S. has already sanctioned hundreds of entities and people in Iran — from the central bank and government officials to drone producers and money exchangers — accused of materially supporting Iran’s Revolutionary Guard and foreign militant groups such as Hamas, Hezbollah and the Houthis.

And U.S. efforts to limit Iran’s income from oil and petroleum products span back decades.

The question remains how effective sanctions will be, and have been, in preventing Iran from ramping up its production of military equipment. American defense officials accuse Iran of supplying drones to Russia as it pursues its invasion of Ukraine, which has reached a third year.

Earlier this week, Treasury Secretary Janet Yellen said during a press conference that the U.S. has “been working to diminish Iran’s ability to export oil.”

”There may be more that we could do,” she said.