Hamas has confirmed Thursday that seven members of its "military wing" were killed when a tunnel collapsed this week in the Gaza Strip.
"Al-Qassam Brigades declare seven Qassam members were martyred in a tunnel collapse in the Gaza Strip," a statement on Twitter from the group said Thursday.
A Hamas source also confirmed the figure to AFP news agency.
The tunnel collapsed late Tuesday in the northeast of the Islamist-ruled enclave after several days of rainfall.
11 Hamas terrorists were in the tunnel at the time, but only three managed to escape.
The statement from the Al-Qassam Brigades said the men killed were working on rebuilding a tunnel previously used for attacks when the collapse occurred. It was not clear if it was referring to the tunnel that collapsed or another connected to it.
Several idle bulldozers could be seen in an area next to a farm where the tunnel is believed to have been located on Thursday morning. The area is about one kilometer from the Israeli border.
Hamas has been working feverishly to rebuild its infiltration tunnel network into Israel, after the IDF destroyed the network during Operation Protective Edge in 2014.
According to some estimates Hamas has already succeeded in digging tunnels into Israel sovereign territory once again, using materials sent by international donors which were earmarked for rebuilding Gaza's civilian infrastructure damaged during the war.
This latest accident reveals such digging can be difficult and dangerous work.