Gaza  - Palestinian paramedics extracted a body from a tunnel beneath Egypt's border with Gaza Strip Sunday, medical officials said, bringing to four the number of dead in the tunnel, with a fifth person missing.

It was unclear whether the four died as a result of poison gas canisters Egyptian security forces tossed into the tunnel on Saturday, or wether they were killed in an Israeli bomb raid.

Egypt has beefed up security measures along its border with the Hamas-controlled Gaza Strip since the end of Israel's 22-day offensive against militants in the salient, and Israel regularly launches air raids on the scores of tunnels which run under the Gaza strip border with the Sinai peninsula.

The tunnels are used to smuggle food and goods into the Strip, and are also a conduit for weapons to reach the enclave. dpa