An Israeli airstrike in south Lebanon on Sunday evening killed four civilians, including a woman and three children, raising the likelihood of a dangerous new escalation in the conflict on the Lebanon-Israel border.

Israeli troops and Hezbollah militants and their allies have been clashing for a month along the border since the start of the Israel-Hamas war. While clashes remain largely contained, they have increased in intensity as Israel conducts a ground incursion in Gaza against Hamas.

Lebanon’s state-run National News Agency reported that two civilian cars carrying members of the same family — one of them a local journalist — were driving between the towns of Ainata and Aitaroun on Sunday evening when they were hit by an Israeli airstrike. One of the cars was hit directly and burst into flames, the report said. One woman and three girls, ages 10, 12 and 14 were killed, and others were wounded, it said.

Shortly after the Israeli strike, Hezbollah said its fighters had fired Grad rockets from southern Lebanon into Israel in response. A number of rockets hit the northern Israeli town of Kiryat Shmona Sunday, Israeli rescue services said. Videos verified by The Associated Press showed a burning car on the street of Kiryat Shmona.

At least one civilian was killed Sunday as a result of attacks by Hezbollah, the Israeli military said, but it wasn’t immediately clear if it was in the Kiryat Shmona attack or an earlier one. Samir Ayoub, the Lebanese journalist, who was in the car in front of the one that was struck, said the three girls killed were his sister’s children and the woman was their grandmother.