A spokesman for the force, Timur Goksel, said that, unlike the Israelis, Lebanese had no civil defence to protect them from attack.

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Israel's Prime Minister Binyamin Netanyahu has warned that there will be military retaliation for rocket attacks by Lebanon-based Hezbollah guerrillas.

That attack was itself a response to an Israeli air raid on Tuesday which killed a Lebanese woman and six of her children.

Israel apologised for that attack, intended for a reported Hezbollah training camp, describing the incident as a "fatal error". Hundreds of mourners were reported shouting anti-Israeli slogans at the funerals.

The UN spokesman questioned how the Israelis could have attacked the woman's house by mistake, pointing out that it was hundreds of miles from the Israeli border and there was no military activity nearby.

Mr Goksel said 28 Lebanese civilians had been killed by Israel this year - despite a ceasefire agreement supposed to protect them.

Dozens of rockets

Hezbollah launched dozens of rockets at the northern Israeli town of Kiryat Shmona early on Wednesday.

At least one building was heavily damaged and several people were injured. Other rockets fell on western Galilee.

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During Wednesday, Israeli forces returned artillery fire against Hezbollah.

Mr Netanyahu, speaking as he toured the area hit in the attacks, said that Israel could not remain silent and would respond in its own time.

Speaking in Kiryat Shemona after an emergency meeting of the security cabinet, Mr Netanyahu said: "We can't let this pass quietly. We will react according to our considerations, when we want. And we will react."

Defence Minister Yitzhak Mordechai said that Israel's fatal attack was completely different to a rocket attack.

"We are sorry about what happened and we apologised," said Mr Mordechai, who had already told Lebanon and its ally Syria that Israel was not seeking further confrontation.

"But the Hezbollah attack was aimed at intentionally killing children on their way to school."

Both Israel and Hezbollah say they do not want to see an escalation of violence in the politically-sensitive border region.

There is also an on-going campaign in Israel to withdraw troops from a security buffer separating the two countries.

Israel's self-declared security zone, which is between 10 and 15km wide, has straddled the border with Lebanon since 1985.

Israel says it needs the zone to protect its territory from Hezbollah attacks.

In an interview with Qatari satellite television, the assistant Secretary-General of Hezbollah, Shaykh Na'im al-Qasim, said: "We carried out these attacks in response to the killing of civilians.

"We believe that Israel must pay a price every time it carries out such an action."