Yemen’s Houthis said on Sunday that they had targeted Israel in coordination with Iran, the first time an Iran-aligned group publicly announced joint cooperation on attacks with Tehran.

The Yemeni group targeted central Israel’s Jaffa with several ballistic missiles in the last 24 hours, military spokesperson Yehya Sarea said in a televised address.

“Triumphing for the oppressed Palestinian and Iranian people...This operation was coordinated with the operations carried out by the Iranian Army against the criminal Israeli enemy,” he added.

The Israeli military earlier said sirens were activated in several areas in the country following missile launches from Iran and Yemen.

On the same day Israel launched its attack on Iran, Israel said a missile that was launched from Yemen towards Israel fell in Hebron in the occupied West Bank. The Yemeni group, however, did not claim responsibility for the missile launch.

Israel targeted a meeting of Houthi leadership in Yemen on Saturday night. An Israeli military official, speaking on the condition of anonymity in line with army rules, said the airstrike targeted Mohamed Al-Ghamari, the Houthi military’s chief of staff.

A senior Houthi political official, Mohammed al-Bukhaiti, told The New York Times that Israel “has not succeeded in targeting any leader” from the group.

“As for us, we are all prepared for martyrdom — from the smallest fighter to the highest-ranking leader,” he said. “We will continue to fight in defense of ourselves and our nation”

The bombing in Yemen raised the possibility that a regional conflict that is already being waged on multiple fronts could escalate.