GAZA - Armed wing of the Islamic Hamas movement, which rules the Gaza Strip, blamed Israel on Sunday for the six deaths of its militants in an ambiguous explosion in Gaza Saturday.

In a statement, Hamas's Qassam Brigades held Israel responsible for the death of its militants, saying that they were killed while "dealing with a booby-trapped spying device."

Six militants of the Hamas armed wing were killed and three others injured Saturday evening in a blast in a house in the Deir al-Balah city in central Gaza Strip.

The group said the device was planted by Israel during the past decade, adding that the deceased militants foiled a "big Israeli spying plan".

The statement said more information on the operation will be revealed later.

"Israel will pay a heavy price," the group said.

Despite Hamas accusations, Israel denied involvement in the explosion.