Egypt has been under pressure to seal off the hundreds of tunnels that are a key economic lifeline for the blockaded Palestinian territory but which are also used to bring in weapons for the Islamic militant group.

Israel and Egypt have kept Gaza's official border crossings closed since Hamas seized control of the coastal strip in 2007 from forces loyal to Western-backed Palestinian President Mahmoud Abbas, who now only governs in the West Bank.

A Hamas security official in charge of the tunnel area along the border said on condition of anonymity that the Egyptians filled the passage with some type of crowd dispersal gas. The Hamas Interior Ministry later said in a statement the gas used to try to clear the tunnel was poisonous. Besides those killed, six people were injured, it said.

An Egyptian border security official refused to comment Wednesday.

"This is a terrible crime against simple Palestinian workers who were trying to earn their daily bread," Hamas spokesman Fawzi Barhoum told AP. " Hamas and all the Palestinian people condemn it strongly."

AP