A surprise Hamas attack in southern Gaza’s Khan Younis on Wednesday shocked Israeli forces and prompted the military to brand the security breach a “failure”.

According to Israeli media, between 15-20 Hamas fighters emerged from a tunnel and separated into three groups: one to enter an unoccupied building, another to enter a building with soldiers stationed inside, and a third to lay down suppressive fire.

The existence of the tunnel had been previously known to the military, and it had been partially demolished, the Times of Israel said.

Fighting reportedly began when an Israeli officer standing on an upper floor opened fire on a fighter below.

A close-quarter firefight lasting around five minutes ensued between the fighters and about 15 soldiers from Israel’s Nahshon Battalion, which required backup from the air force and a tank.

According to the Israeli reporters, the battle lasted around three hours and no Israelis were killed. Three soldiers were wounded in the attack, the military said, one of them seriously.

Hamas, meanwhile, said its fighters “eliminated several occupation soldiers”, including “the commander of a Merkava 4 tank, fatally wounding him”.