WASHINGTON — An Israeli airstrike against Syria was targeting a shipment of advanced missiles believed to be bound for the Lebanese militant group Hezbollah, Israeli officials confirmed today.

It was the second Israeli strike this year against Syria and the latest salvo in its long-running effort to disrupt Hezbollah’s quest to build an arsenal capable of defending against Israel’s air force and spreading destruction inside the Jewish state.

The strike comes as the U.S. considers how to respond to indications that the Syrian regime may have used chemical weapons in its bloody civil war. President Barack Obama has described the use of such weapons as a “red line,” and the administration is weighing its options — including possible military action.

Israeli Prime Minister Benjamin Netanyahu has repeatedly warned in recent weeks that Israel would be prepared to take military action if chemical weapons or other arms that would upset the balance of power with Hezbollah were to reach the Islamic militant group.

The Israeli officials said the attack Friday was aimed at sophisticated “game-changing” weapons, but not chemical arms.