The Israeli military said it launched a wave of strikes on Beirut claiming to target the Iran-backed group Hezbollah early Saturday, while Lebanese state media reported strikes in the country's south.
Lebanon was pulled into the Middle East war when Hezbollah began firing rockets into Israel on March 2 to avenge the killing of Iran's supreme leader Ali Khamenei.
Israel has since launched strikes across Lebanon and sent ground troops into the country's south.
In a brief statement on Saturday, the Israeli military said its forces were "currently striking Hezbollah terrorist organization targets in Beirut".
A military spokesman earlier issued a warning to residents of Beirut's southern suburbs, a Hezbollah stronghold, to evacuate ahead of strikes.
Lebanon's official National News Agency (NNA) reported strikes on two neighborhoods in the area, without immediately saying what had been hit or whether there were any casualties.
In southern Lebanon, close to the border, the NNA said an Israeli airstrike hit a house in the town of Ghandouriyeh, killing at least one person and wounding two others.
The agency reported more strikes overnight and in the early morning on several areas of southern Lebanon, as well as an "extensive combing operation" carried out by Israeli troops in the area of Khiam town.
Hezbollah also said its fighters had targeted Israeli troops in six villages in southern Lebanon.
The group said it had also launched rockets across the border, where air raid sirens were activated, according to the Israeli military's Home Front Command.
The US ambassador to Lebanon, Michel Issa, gave his backing on Friday to a truce initiative proposed by Lebanese President Joseph Aoun, telling reporters that "matters are not resolved without talking".
He said, however, he believed Israel "has decided not to stop" striking Lebanon yet.
"That means Lebanon has to decide whether it can meet the Israelis in this case," the ambassador added.
Lebanon's health ministry says the war has killed more than 1,000 people in Lebanon and displaced more than one million more.
Two Israeli soldiers have been killed in southern Lebanon, according to the military.