Palestinians say Egypt’s crackdown, which began in March and has included flooding of underground passages, was stepped up in the past two weeks.

Egypt's military has pledged to shut all tunnels under the Gaza border, alleging that they are used to smuggle activists and weapons.

The moves against the tunnels have dashed the hopes of many Palestinians that Egypt’s President Mohamed Morsi would significantly ease Egyptian border restrictions on Gaza after taking power in 2011.

Only 50 to 70 tunnels, out of hundreds that have provided a commercial lifeline for the Gaza Strip, are still open and in partial operation, Palestinians say.

Gaza has been blockaded by the Israeli regime since June 2007. The situation has caused a decline in the standards of living, unprecedented levels of unemployment, and unrelenting poverty.