An Israeli air strike on a building in the Lebanese capital Beirut targeting a member of Hezbollah has killed at least four people.

The surprise attack came at about 3:30am (00:30 GMT) on Tuesday during the Eid al-Fitr Muslim holiday marking the end of the Ramadan fasting month. The second strike on the city in three days has raised fears that the shaky ceasefire between Israel and the armed Hezbollah group that took effect four months ago could collapse.

The Lebanese Ministry of Health said the four people killed included a woman and that seven others were wounded.

Israel’s military said in a statement that it had targeted Hassan Bdeir, a member of a Hezbollah unit and Iran’s Quds Force, who was assisting the Palestinian armed group Hamas in planning a “significant and imminent terror attack against Israeli civilians”.

The Israeli army did not offer any evidence for the statement. There was no immediate comment from Hezbollah.

The strike followed just days after a previous hit on the southern suburb of Dahiyeh, a Hezbollah stronghold.

Lebanon’s President Joseph Aoun condemned the latest assault, calling it a “dangerous warning” of Israel’s intentions against his country.

“Israel’s persistence in its aggression requires more effort from us in addressing Lebanon’s friends around the world and rallying them in support of our right to full sovereignty over our land,” Aoun said in a statement.

Lebanese Prime Minister Nawaf Salam also condemned the Israeli strike and said it was a flagrant breach of United Nations Resolution 1701 and the ceasefire arrangement. Salam said he has been closely monitoring the aftermath of the strike in coordination with the ministers of defence and interior.

Al Jazeera’s Resul Serdar, reporting from Beirut, said rescue operations were ongoing and added that the latest attack is “extremely worrying” for the Lebanese government, as it comes just three days after Israeli forces bombed Beirut for the first time since the ceasefire deal with Hezbollah in November.

The agreement, guaranteed by France and the United States, brought a halt to a yearlong conflict and mandated that Israeli ground troops withdraw from southern Lebanon.

It also called for Hezbollah fighters to withdraw from the south, and for Lebanese troops to deploy there.

Both sides, however, have accused each other of violations.