Egyptian forces have flooded smuggling tunnels under the border with the Palestinian-ruled Gaza Strip in a campaign to shut them down, Reuters reported citing Egyptian and Palestinian officials.
The network of tunnels is a vital lifeline for Gaza, bringing in an estimated 30 percent of all goods that reach the enclave and circumventing a blockade imposed by Israel for more than seven years.
Reuters reporters saw one tunnel being used to bring in cement and gravel suddenly fill with water, sending workers rushing for safety. Locals said two other tunnels were likewise flooded, with Egyptians deliberately pumping in water.
"The Egyptians have opened the water to drown the tunnels," said Abu Ghassan, who supervises the work of 30 men at one tunnel some 200 meters (yards) from the border fence.
An Egyptian security official in the Sinai said the campaign started five days ago.
"We are using water to close the tunnels by raising water from one of the wells," he said, declining to be named.
Dozens of tunnels had been destroyed since last August following the killing of 16 Egyptian soldiers in a militant attack near the Gaza fence.
Cairo said some of the gunmen had crossed into Egypt via the tunnels - a charge denied by Palestinians - and ordered an immediate crackdown.
The move surprised and angered Gaza's rulers, the Islamist group Hamas, which had hoped for much better ties with Cairo following the election last year of Egyptian President Mohamed Mursi, an Islamist who is ideologically close to Hamas.
A Hamas official confirmed Egypt was again targeting the tunnels. He gave no further details and declined to speculate on the timing of the move, which started while Palestinian faction leaders met in Cairo to try to overcome deep divisions.