Israeli Prime Minister Benjamin Netanyahu vowed Thursday that Israel would defend its land, air and sea borders, during a tour to the just-completed 240-km high- tech barrier with Egypt.

"We are determinedly protecting our borders," Netanyahu said, " as we have done and continue to do on land, as here with the fence which has stopped the infiltrators and stops terrorism, (and) in the air, (as) over the weekend with the foiling of the Hezbollah attempt."

On Saturday, Israeli air force jets shot down an unmanned drone that entered southern Israeli airspace from the Mediterranean Sea.

Israeli analysts said the Lebanon-based, Iranian-backed Shiite group Hezbollah sent the device to surveil sensitive military sites along the coast and the Dimona nuclear research facility.

Five infiltrators have tried to get through the barrier since the beginning of October, but all were stopped, the Prime Minister 's Office said in a statement sent to Xinhua.

The electronically-monitored high steel fence that now separates Israel from the Sinai Peninsula is intended to thwart infiltrators -- whether asylum-seekers, refugees and those seeking work, smugglers, or cross-border terror attacks which have become frequent over the last 12 months.

The latest incident took place in September, when a group of eight heavily-armed gunmen ambushed a group of Israeli soldiers who were assisting African migrants stranded along a desolate 17- km stretch about midway between Gaza and the Red Sea.

The gunmen, exploiting the infiltrators as bait to draw Israeli forces close to the fence, then opened fire on the troops, killing one Israeli soldier and wounding another.

Construction of the massive barrier began in 2010 and has cost Israel over 1.5 billion shekels (about 400 million U.S. dollars).