Israel carried out a series of massive airstrikes overnight in southern suburbs of Beirut and another that cut off the main border crossing between Lebanon and Syria.

The new wave of strikes came after Israel warned people to evacuate communities in southern Lebanon that are outside a United Nations-declared buffer zone, as the yearlong conflict between Israel and the Lebanese militant group Hezbollah escalates.

Israel launched a ground incursion into Lebanon on Tuesday and its forces have been clashing with Hezbollah militants in a narrow strip along the border. A series of attacks before the incursion killed some of the group's key members, including longtime leader Hassan Nasrallah.

The blasts overnight rocked Beirut's southern suburbs, sending huge plumes of smoke and flames into the night sky and shaking buildings kilometres (miles) away in the Lebanese capital. The Israeli military did not immediately comment on what the intended target was, and there was no information immediately available on casualties.

Lebanon's state-run National News Agency reported that there were more than 10 consecutive airstrikes in the area late Thursday.

The agency also reported that an Israeli airstrike led to the closure of the road near the busy Masnaa Border Crossing, from which tens of thousands of people fleeing war in Lebanon have crossed into Syria over the past two weeks. It gave no other details.

The airstrike that cut the busiest border crossing between the two countries came a day after an Israeli military spokesperson said Lebanon's Hezbollah has been trying to transport military equipment through the border crossing.

Hezbollah is believed to have received much of its weaponry from Iran via Syria. The group has a presence on both sides of the border, a region where it has been fighting alongside Syrian President Bashar Assad's forces.

Dama Post, a pro-government Syrian media outlet, said Israeli warplanes fired two missiles, damaging the road between Masnaa Border Crossing in Lebanon and the Syrian crossing point of Jdeidet Yabous.

It was the first time this major border crossing has been cut off since the beginning of the war. Lebanese General Security recorded 256,614 Syrian citizens and 82,264 Lebanese citizens crossing into Syrian territory between Sept 23 — when the Israel launched a heavy bombardment of southern and eastern Lebanon — and Sept 30.

There are half a dozen border crossings between the two countries and most of them remain open. Lebanon's minister of public works said all border crossings between Lebanon and Syria work under the supervision of the state.

Israel and Hezbollah have traded fire across Lebanon's southern border almost daily since the day after Hamas' cross-border attack on Oct 7, 2023, in which the militants killed 1,200 Israelis and took 250 others hostage.

Meanwhile, the Israeli army said it carried out a strike Thursday in Tulkarem, a militant stronghold in the West Bank, in coordination with the Shin Bet internal security service.

The Palestinian Health Ministry said 18 people were killed in an Israeli strike on a refugee camp there.

Violence has flared across the Israeli-occupied territory since the Israel-Hamas war erupted in October 2023. Tulkarem and other northern cities have seen some of the worst violence.

Israel declared war on Hamas in the Gaza Strip in response to their Oct 7 attack. More than 41,000 Palestinians have since been killed in the territory, and just over half the dead have been women and children, according to local health officials. Nearly 2,000 people have been killed in Lebanon in that time, most of them since Sept 23, according to the Lebanese Health Ministry.