Gaza City: Seven members of Hamas' military wing were killed when a tunnel built for fighting against Israel collapsed this week in the Gaza Strip, the Islamist movement said on Thursday.
The Ezzedine Al-Qassam Brigades, Hamas's armed wing, said in a statement that four militants managed to escape after the collapse late on Tuesday in the northeast of the Palestinian enclave.
The collapse occurred after several days of rain.
Al-Qassam Brigades said the seven "martyrs" were killed "when they were going to prepare for fighting with the enemy."
Eight militants were initially reported missing by a security source. A Hamas source said three managed to escape within the first hour of the collapse, while a fourth was later rescued.
The man rescued was injured, the source said, but it was not clear how seriously. Hamas officials were seeking to keep tight control over information regarding the incident.
The collapse comes at a time of renewed focus on tunnels in Gaza, with Israel accusing Hamas of reconstructing them with the aim of attacking it following its 2014 war with Palestinian militants in the enclave when many were destroyed.
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 on Thursday morning in an area next to a farm where the tunnel is believed to have been located. The area is about a kilometre (mile) from the Israeli border.
Tunnels on TV
Such tunnels have been used in the past to store weapons or stage attacks, including by passing under the Israeli border during the 2014 war.
After the statement on the deaths was issued on Thursday, Hamas-run Al-Aqsa television broadcast a programme on tunnel operations, including the targeting of Israeli tanks.
Such collapses have previously occurred in the coastal strip, which is under an Israeli blockade and has seen three wars with the Jewish state since 2008.
On Saturday, a tunnel collapse killed a 30-year-old man, according to Hamas officials. Residents said the tunnel was located in Al-Maghazi in the central Gaza Strip.
In December, 14 Palestinians were rescued after being stranded for hours in a tunnel near the Egyptian border when it flooded and partially collapsed, though tunnels in that area are more typically used for smuggling.
At the end of 2014, Egypt began the construction of a buffer zone in the northern Sinai Peninsula, on the border with Gaza, including destroying hundreds of tunnels it says are used for smuggling weapons and other items.
Israel's blockade severely restricts the movement of people and goods into and out of the enclave.
Egypt's sole border with Gaza has also remained largely closed following the 2013 overthrow of the country's president Mohamed Morsi of the Muslim Brotherhood, effectively trapping the 1.8 million Gazans into the territory.