Efforts by Egyptian authorities to close smuggling tunnels between the Gaza Strip and Sinai by flooding them with water are not working because smugglers are using pumps to keep the subterranean passages open.

Egyptian military sources said they will step up operations against the tunnels as they have as yet been unsuccessful, according to a report by Israel Radio on Wednesday which quoted the Palestinian Ma’an news agency.

The source said that Egyptian army engineering units are preparing to bring heavy equipment to bear on the tunnels. The engineering units will be provided with special military protection as they work to destroy the passages in order to prevent attacks by smugglers hoping to save the underground infrastructure.

Gaza, which is home to 1.7 million people, has lived with border restrictions by Israel and Egypt since the Hamas takeover of the territory in 2007. Smuggling under the 15-kilometer (9-mile) border has circumvented official crossings and bypassed restrictions for many years.

Israel restricts the influx of goods into the territory from its side of the enclave, so Gazans smuggle in construction materials, cars and fuel. The tunnels are also used to bring cash and weapons into the Hamas-controlled enclave where they are then used against Israel.

Hamas earns revenue by taxing goods that are brought in the Strip via the tunnels. However, following a terrorist attack on an Egyptian army base in August 2012 that killed 16 border guards in the Sinai Peninsula, Cairo authorities have campaigned to shut down tunneling operations.

At the beginning of last month Egyptian forces began pumping water into the tunnels to force their closure and at the end of February an Egyptian court ruled that the smuggling tunnels are a security threat to Egypt and must be destroyed.