The Israel Air Force has reportedly rushed fighter jets to the border with Lebanon after a suspicious aircraft was detected approaching its airspace.

Two jets and an attack helicopter were rushed to the border after an unidentified aircraft was spotted flying very close to the border, Jerusalem Post daily said.

The aircraft, together with ground forces, conducted searches on the ground and shortly later returned to base after the plane turned around and flew back north into Lebanon, it added.

The Israeli Army was on a high level of alert throughout the country during the holiday and particularly in the north, where intelligence officials have said it is possible that Hizbullah will carry out a cross-border attack to avenge the assassination of Imad Mughniyeh earlier this year.

The Jerusalem Post reported that while the IDF is concerned that Hizbullah will try to kidnap soldiers, current fears are that militants will cross into Israel, fly an explosives-laden drone or infiltrate a border community like Shlomi and barricade themselves inside a home with civilian residents.

The defense establishment is concerned that Hizbullah will use the holidays, as well as the switchover in government - from Prime Minister Ehud Olmert to Kadima Party head Tzipi Livni - to launch an attack, the report added.

Intelligence assessments, the report said, have raised the possibility that Hizbullah believes that with Olmert heading a transitional government and Livni still working on forming a coalition, neither one will want to respond harshly to an isolated Hizbullah attack and risk another war.