With Iran-backed Hezbollah on the defensive after a series of heavy Israeli blows, the United States and Iran are locked in a showdown over Lebanon's future, analysts said.
Hezbollah, the most powerful regional force backed by Iran, which arms and finances it, has long held sway in Lebanon.
But the group's influence is now in question after Israel's assassination of its leader, Sayyed Hassan Nasrallah, in a significant setback.
Hezbollah's losses have left Lebanon in a "tug of war between Iran and the United States," said Michael Young of the Carnegie Middle East Center think tank.
"The Israelis with the Americans... are trying to use military force to try to transform the balance of power in Lebanon to their advantage," he told AFP.
"There are no signs that the Iranians are going to accept this without a fight."
Hezbollah is considered better armed than Lebanon's national military and remains the only group that did not put down its weapons after the 1975-90 civil war.
Last year, it opened a new front with Israel over the conflict in Gaza, in support of its ally Hamas.
It carefully calibrated attacks to avoid a full-blown conflict, which eventually came on September 23 when Israel stepped up bombing of Hezbollah strongholds, including south Beirut.