Egypt has denied claims it deliberately pumped poisonous gas into a cross-border tunnel into the Gaza Strip, killing four Palestinians.

Hamas leaders in Gaza have accused Egyptian security forces of pumping toxic gas into a tunnel, killing four men and injuring several others.

Doctors in Gaza say all four died from suffocation and there was evidence of a poisonous gas.

Hamas is demanding a full investigation and action against those responsible.

Egypt has rejected the accusation as entirely false, although it admits its security forces did destroy four tunnels after the men’s deaths.

Egypt has recently intensified efforts to block the tunnels to stop smuggling, even building an underground wall to cut them off.