Israel has begun preparations for a "limited ground incursion" into Lebanon, according to US officials, as tensions escalate along the Israel-Lebanon border with increasing exchanges of fire and targeted strikes.

Israeli forces have been amassing near the Lebanese border, and the Israeli military has declared areas close to the frontier as closed military zones. This comes as Israel continues its campaign of targeted killings, striking central Beirut for the first time since the conflict began and following the killing of Hezbollah leader Hassan Nasrallah.

Three members of the Popular Front for the Liberation of Palestine were killed in the Beirut strike earlier in the day, while a separate Israeli airstrike on a Palestinian camp in southern Lebanon resulted in the death of a senior Hamas commander.

A Lebanese soldier was also reported killed by an Israeli drone strike, marking the first Lebanese military casualty since the outbreak of hostilities.

Israeli Defence Minister Yoav Gallant hinted at a possible ground operation against Hezbollah, stating that "eliminating [Hezbollah leader Hassan] Nasrallah is an important step, but not the last one."

US officials, speaking on condition of anonymity, revealed that Israel had informed Washington of plans for a limited ground incursion into Lebanon, with Israeli media reporting Israeli tank and artillery fire inside southern Lebanon, suggesting they had already crossed the border.

The operation is expected to target Hezbollah infrastructure near the border, with the incursion targeting key Hezbollah depots in the border area.

Meanwhile, Hezbollah continues to launch rockets at Israeli targets in retaliation. The Israeli military reported intercepting a drone that entered its northern economic waters, allegedly targeting the Karish gas field.

The death toll from recent Israeli strikes in Lebanon has risen significantly, with multiple incidents causing civilian casualties.

The Lebanese Health Ministry reported at least 45 dead and 70 injured in a single strike on a building in the Ain el-Delb area east of Sidon.

The US is sending an additional "few thousand" troops to the Middle East to bolster security and to be prepared to defend Israel if necessary, the Pentagon said.