The collapse of a tunnel in the Gaza Strip has killed two militants from Hamas's armed wing, officials said today, as concern grows in Israel over the rebuilding of tunnels that can be used for attacks.

The collapse last night was the second such incident since last week. A tunnel collapse on January 26 killed seven militants from Hamas, the Islamist movement that rules the Gaza Strip.

Hamas's armed wing, the Ezzedine Al-Qassam Brigades, said a local commander was among the two members killed in the collapse in the area of the Nuseirat refugee camp in the central Gaza Strip.

Ismail Haniya, Hamas's chief in Gaza, has vowed to continue building tunnels that have in the past been used to stage attacks against Israel and store weapons.

Israel destroyed a large number of tunnels in the 2014 Gaza war, the third conflict to hit the Palestinian enclave since 2008.

Israeli Prime Minister Benjamin Netanyahu has warned that "if we are attacked from tunnels from the Gaza Strip, we will take very strong action against Hamas.