The reports cited Milos Strugar, spokesman of the United Nations Interim Force in Lebanon (UNIFIL), as saying that an Israeli bomb directly hit the base of the United Nations Observer Group in the southern Lebanese border town of Khiam.

The base was manned by Indian UN soldiers and some casualties were caused, according to Strugar.

An rescue team was trying to clear the rubble, he added, without giving the exact number of casualties.

Meanwhile, local Lebanese TV reported that four UN observers were killed in the Israeli air raid.

Earlier, the pan-Arab al-Jazeera satellite channel reported that five Indian UN peacekeeping soldiers were killed in an Israeli airstrike on south Lebanon.

The Israeli army continued airstrikes across Lebanon on Tuesday and small units of Israeli forces were in south Lebanon to mount "pinpoint" attacks against strongholds of the Lebanese Shiite group Hezbollah.

On Monday, four Ghanaian UN peacekeepers were injured when an Israeli tank shell hit their position near the southern Lebanese village of Rmeish.

On Sunday, an Italian UN observer was wounded by Lebanese Hezbollah guerillas' fire during clashes against Israeli forces in the southern Lebanese border village of Maroun al-Ras.

Created in 1978 and deployed in south Lebanon since then, UNIFIL has been committed to confirming the Israeli withdrawal from Lebanon, restoring the international peace and security and helping the Lebanese government restore its effective authority in the area.

Violence erupted in Lebanon on July 12 when Israel started a massive assault following the capture of two Israeli soldiers by Hezbollah guerillas in cross-border attacks.