The armed wings of Palestinian fighter groups Hamas and Islamic Jihad said Wednesday they were targeting southern and central Israel with rockets, as sirens sounded in areas surrounding the Gaza Strip.
Al-Quds Brigades, the armed wing of Islamic Jihad, said it was targeting the Israeli cities of Tel Aviv, Ashdod and Ashkelon as well as communities near the Gaza border with "heavy rocket fire".
Ezzedine Al-Qassam Brigades, the armed wing of Hamas, said it had fired a rocket at Ben Gurion airport, where Israeli officials reported no hit.
Hezbollah fires missiles into Israel
Lebanon's Hezbollah said it fired missiles on Israel Wednesday drawing retaliatory fire, after three members of the Iran-backed group were killed earlier this week amid soaring border tensions.
The latest exchange of fire came as Israel massed troops and heavy armour around Gaza in its retaliatory campaign against Hamas militants in a conflict that has left hundreds dead on both sides.
Hezbollah "targeted a Zionist (Israeli) position... facing Dhayra village, with guided missiles," in a "firm response to Zionist attacks... which led to the martyrdom of a number of brothers," the group said in a statement.
It warned of a "decisive" response to Israeli attacks "targeting our country and the security of our people, especially when these attacks lead to the deaths of martyrs".
The Israeli military said that "in response to the anti-tank missile fired at IDF (army) soldiers a short while ago, an IDF aircraft struck a military observation post belonging to the Hezbollah terrorist organisation in southern Lebanon".
Israeli artillery shelled "the area from which the launch originated," the military added.
US President Joe Biden has said Washington was "surging assistance" for Israel, including missiles for its Iron Dome interceptor system, while the largest US aircraft carrier has been ordered to move closer to Israel.
Hezbollah lambasted Biden's stance, saying the diversion of the aircraft carrier battle group "revealed the weakness of the Zionist (Israeli) military machine... and its need for continuous external support".
"This step will not frighten... resistance factions that are ready for confrontation," Hezbollah said.
- 'Prepared for any scenario' -
Lebanon's state-run National News Agency (NNA) said Israeli fire on a border village wounded three civilians, adding that "around 10 houses have been directly hit".
An AFP correspondent in the border village of Dhayra earlier reported shelling close to residential areas that triggered fires in nearby groves.
The NNA said Israeli fire on several locations along the border had been "countered by resistance (Hezbollah) machine guns".
On Monday, Hezbollah said three of its members had been killed in Israeli strikes on south Lebanon after Palestinian militants tried to slip across the border.
Both Israel and its closest ally the United States have warned Hezbollah against opening a second front as Israel battles Hamas in Gaza.
The Israeli army is "prepared for any scenario", spokesman Daniel Hagari told reporters.
"Hezbollah is observing what Israel is doing in Gaza, it sees the volume of the destruction. Hezbollah sees this and understands," he said.
Israel has been retaliating to daily fire from Lebanon, which began after Hezbollah launched rockets on a disputed border area on Sunday.
The Lebanese army said it had found "the rocket launcher that fired a number of rockets" on Tuesday -- an attack that Hamas said it carried out.
In Israel, the death toll from Hamas's shock cross-border assault rose to 1,200, mostly civilians, while Gaza officials reported more than 1,000 people killed as Israel pounded the territory with air strikes.
In 2006, Hezbollah and Israel fought a devastating 34-day war that left more than 1,200 people dead in Lebanon, mostly civilians, and 160 in Israel, mostly soldiers.
Rocket hits Israel hospital
A rocket fired from the Gaza Strip struck a hospital in the southern Israeli city of Ashkelon on Wednesday, a spokeswoman for the healthcare facility said.
"The child development centre at the Barzilai hospital in Ashkelon suffered a direct hit by a projectile from Gaza," she said in a statement.
Contacted by AFP, she said there were no casualties.