Israel on Sunday launched attacks against 18 targets allegedly belonging to militant groups in Gaza, in response to an explosion which wounded four soldiers on the border fence, Reuters reported. The Israeli military said it had launched air strikes and tank fire against targets belonging to extremist groups Hamas and Islamic Jihad.

The military added that eight of the targets were located in a Hamas military compound, Haaretz reported. An Israeli tank also attacked two Hamas observation posts, the military said. A tunnel built by Hamas reaching from Gaza into Israeli territory was pounded.

Unidentified medics in Gaza told Reuters that they retrieved the bodies of two 17-year-old Palestinians killed by Israeli tank fire.

Israeli Defence Minister Avigdor Lieberman said the Popular Resistance Committees, an armed group in Gaza, had detonated the bomb that wounded soldiers on Saturday. “We will hunt down those responsible for yesterday’s incident,” Lieberman said.

Hamas spokesperson Fawzi Barhoum blamed Israel for the violence. “Hamas holds the Israeli occupation fully responsible for the consequences of its continued escalation against our people.”

On Saturday, Israel Prime Minister Benjamin Netanyahu had said at security conference in Munich that the attack on Israeli soldiers was a “very serious” incident, The Times of Israel reported. “We will respond appropriately,” he added.