The U.S. and U.K. on Thursday imposed a new round of sanctions on Iran as concern grows that Tehran’sunprecedented attack on Israel could fuel a wider warin 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. Additionally, the U.K. is targeting several Iranian military organizations, individuals and entities involved in Iran’s drone and ballistic missile industries.

“We will continue to deploy our sanctions authority to counter Iran with further actions in the days and weeks ahead," Treasury Secretary Janet Yellen said in a statement.

The action comes after U.S. officials earlier this weekwarned that they were readyingnew 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 leadersalso vowed on Wednesdayto 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.”