As Israel pounded targets in the Gaza Strip from the air and sea on Wednesday, a member of the country’s war cabinet threatened action on a second front, along the border with Lebanon, where the Iranian-backed militia Hezbollah has fired rocket barrages into Israel.

“I say to our friends around the world: The situation in the northern border necessitates change,” the war cabinet member, Benny Gantz, told reporters. “The time for a diplomatic solution is running out. If the world and the government of Lebanon don’t act to stop the fire toward northern communities and to push Hezbollah away from the border, the I.D.F. will do that.” The reference was to the Israel Defense Forces.

The threat of a wider war has preoccupied the United States and its allies since the start of the conflict in Gaza, and has only grown as three Iranian-backed groups — Hamas, Hezbollah and Houthis in Yemen — launch attacks toward Israel as well as on commercial ships in the Red Sea. The concern prompted the United States to dispatch two aircraft carriers to the Eastern Mediterranean in the weeks after the Oct. 7 Hamas-led attacks on Israel that sparked the war in Gaza.

The Israeli military said Wednesday that its northern command, along the border with Lebanon, was in a “state of very high readiness.” The military’s chief of staff, Lt. Gen. Herzi Halevi, said, “We need to be prepared to strike if required.”

Tensions rose even higher this week after Iran accused Israel of killing Brig. Gen. Sayyed Razi Mousavi, a senior adviser to Iran’s Islamic Revolutionary Guards Corps, in a missile strike in Syria. On Wednesday, a cortège of mourners accompanied his body through the Iraqi cities of Najaf and Karbala, and a representative of the Revolutionary Guard, Ramezan Sharif, again threatened retaliation against Israel, The Associated Press reported.