Yemen’s Houthi rebels are stepping up their missile attacks, keeping up what could be the last major front in the Middle East wars.

The US military on Tuesday said it hit targets in Yemen targeting the Houthi militia, hours after the Iran-backed group launched attacks on Israel. The United States Central Command (CENTCOM) said its warships and aircraft attacked a number of Houthi-linked sites,

Houthi rebels in Yemen said Israeli airstrikes on Thursday targeted the rebel-held capital of Sanaa and the port city of Hodeida, following several days of Houthi launches setting off sirens in Israel.

The head of the World Health Organization said he was about to board a flight in the Yemeni capital when the airport came under bombardment.

Israel’s military says it intercepted a missile fired toward the country by Yemen’s Houthi rebels. The attack set off sirens late Monday in central areas of Israel, including Tel Aviv.

The military said the missile was intercepted before crossing into Israeli territory, but police reported shrapnel from the interception fell in several towns. There were no reports of injuries.

Israel said it had repelled an attack, which came hours after Israel’s defense minister vowed to “behead” the Yemeni group’s leadership.