Israel's civilian air traffic was halted for several minutes on Wednesday morning after an unidentified flying object was spotted inside Israeli air space, Israel's army radio said.

Air force jets were briefly scrambled and Israeli air space was closed, it said, without saying what caused the scare. The closure was lifted several minutes later.

Closing Israeli air space was an "exceptional" measure which demonstrated the level of tension in Israel after the air force shot down an unidentified and unarmed drone which had entered the country's airspace on Saturday from the Mediterranean.

Fresh details about the weekend incident emerged on Wednesday with both army radio and the top-selling Yediot Aharonot daily saying the air force had only managed to shoot down the drone on the second attempt.

Both reports said that the first missile fired by the F-16 jet missed the drone which was eventually brought by a Panther missile, the military's most advanced air-to-air projectile.

Senior air force sources quoted by Yediot played down the incident saying it was not unreasonable given the drone's small size.

"This is not a failure, no other army in the world with Israel's aerial defence systems could prevent the infiltration of such aircraft."

The military had no immediate comment on Wednesday's false alarm, nor did they comment on the report suggesting the F-16 had only downed the drone on a second attempt.

At the time, the military described the operation as a "success" but did not go into details about how the unmanned aerial vehicle (UAV) was intercepted.

Military officials are investigating where the drone came from, with suspicions it was operated by Hezbollah, the Lebanese Shiite militia.

In July 2006, Israel shot down another unarmed drone operated by Hezbollah over the Jewish state's territorial waters.

A year earlier, in April 2005, another pilotless Hezbollah aircraft succeeded in overflying part of northern Israel without being downed.