Yemen’s Houthi rebels have launched their largest-ever barrage of missiles and drones targeting shipping in the Red Sea, causing both the United States and British navies to shoot down the projectiles in a significant naval engagement.

The attack by the Iranian-backed Houthis came in the face of a planned United Nations Security Council vote on Wednesday to potentially condemn such actions.

This proposal would also call for an immediate halt to attacks by Houthis, who say their assaults are aimed at stopping Israel’s war against Hamas in Gaza.

However, their targets increasingly have very little connection to Israel.

The spike in violence threatens a crucial trade route linking Asia and the Middle East to Europe, which heightens the risk of a U.S. retaliatory strike on Yemen.