(Reuters) — Friday’s U.S. airstrikes against Iran-backed militias in eastern Syria encourage terrorism in the region, Iran’s top security official, Ali Shamkhani, said on Saturday.

Washington said the strikes on positions of the Kataib Hezbollah (KH) paramilitary group along the Iraq border were in response to rocket attacks against U.S. targets in Iraq.

“America’s recent action strengthens and expands the activities of the terrorist Daesh (Islamic State) in the region,” Shamkhani, the Secretary of Iran’s Supreme National Security Council, said in remarks to visiting Iraqi Foreign Minister Fuad Hussein.

“The attack on anti-terrorist resistance forces is the beginning of a new round of organized terrorism,” the semi-official Nour News quoted him as saying.

Hussein, on his second visit to Iran in a month, later met with his Iranian counterpart Mohammad Javad Zarif.

Hussein is in Iran “to discuss regional developments, including ways to balance relations and avoid tension and escalation” with Iranian officials, according to an Iraqi foreign ministry statement.

An Iraqi militia official close to Iran said the strikes killed one fighter and wounded four. U.S. officials said they were limited in scope to show President Joe Biden’s administration will act firmly while trying to avoid a big regional escalation.

Shamkhani said “we will confront the U.S. plan to revive terrorism in the region”, but did not elaborate.

The air strikes targeted militia sites on the Syrian side of the Iraqi-Syrian frontier, where groups backed by Iran control an important crossing for weapons, personnel and goods.

Western officials and some Iraqi officials accuse Iranian-backed groups of involvement in deadly rocket attacks on U.S. sites and personnel in Iraq over the last month.

Washington and Tehran are seeking maximum leverage in attempts to save Iran’s nuclear deal reached with world powers in 2015 but abandoned in 2018 by then-President Donald Trump, after which regional tensions soared.