Israel’s military said Monday that it destroyed an attack tunnel that led into its territory from the Gaza Strip, killing at least seven Palestinian militants, including a senior commander of the Islamic Jihad group and two members of Hamas.

The tunnel crossed from the area of Khan Younis in Gaza and was still under construction, according to Lt. Col. Jonathan Conricus, a spokesman for the Israeli military.

Islamic Jihad, the second-largest armed faction in Gaza after Hamas, said five of its members were killed, including the commander of its military wing in central Gaza. The group described the destruction of the tunnel as a “dangerous escalation” and said it reserved the right to respond to the “terrorist aggression.”

Hamas said two of its militants were killed during a rescue mission after the tunnel was targeted.