Hamas “heroes” are tirelessly digging Gaza Strip tunnels designed for use in attacks on Israel, a senior official said Friday, as the terror group buried seven excavators killed this week when the tunnel they were working on collapsed due to heavy rains and floods.

Thousands turned out for the funerals in the Hamas-ruled Gaza, Army Radio reported, where Ismail Haniyeh vowed that the group is growing stronger and will use any measures to preparation for the next confrontation with Israel.

“Some believe that the calm, when the noise of the cannons fall silent, is intended for rest. But the [Izz ad-Din] al-Qassam Brigades continue with their campaign through preparation and training,” said Haniyeh, referring to the Hamas military wing. The resistance, he said, is permanently in a state of continuous preparation.

“East of Gaza City, heroes are digging through rock and building tunnels, and to the west they are experimenting with rockets every day. The resistance continues on its path of liberation of the land,” Haniyeh said during the funerals at the Great Omari Mosque in Gaza City.

Wrapped in green Hamas flags, the seven bodies were carried to the mosque while crowds chanted slogans calling for violence against Israel.

In a rare move, several Hamas leaders went to the cemetery located near the border with Israel to place flowers by the graves of the seven fighters.

The seven Hamas diggers were killed when their tunnel collapsed Tuesday in the area of Jabalia, in the north of the Palestinian enclave after several days of rainfall, a security source in the area said on condition of anonymity.

Palestinian Hamas leader in Gaza, Ismail Haniyeh, gives a speech during a rally in Gaza City, Aug. 27, 2014. (AP/Khalil Hamra)

Palestinian Hamas leader in Gaza, Ismail Haniyeh, gives a speech during a rally in Gaza City, Aug. 27, 2014. (AP/Khalil Hamra)

“The resistance tunnel collapsed last night due to the weather and flooding,” the source said, adding that the tunnel belonged to Hamas.

Izz ad-Din al-Qassam Brigades later confirmed in a statement that one of its tunnels had collapsed.

It comes at a time of renewed focus on tunnels in Gaza, with Israel accusing Hamas of reconstructing them following its 2014 war with Palestinian militants in the enclave when many were destroyed.

Israel says the tunnels could be used to carry out fresh attacks against it.

Such collapses have previously occurred in the coastal strip, which is under an Israeli and Egyptian naval blockade and has seen three wars with the Jewish state since 2008.

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 said were used for smuggling weapons.

Still from an August 2015 Hamas video purporting to show a Gaza tunnel dug under the Israeli border (Ynet screenshot)

Still from an August 2015 Hamas video purporting to show a Gaza tunnel dug under the Israeli border (Ynet screenshot)

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.

Gaza has remained largely calm since a wave of Palestinian knife, gun and car-ramming attacks began in October in the West Bank, Jerusalem and across Israel, though a number of people have been killed by Israeli forces during violent protests along the Gaza border.