(CNN) -- An Egyptian court ordered authorities Tuesday to destroy tunnels between the country and Gaza -- the latest sign of a crackdown on underground smuggling networks.
It's unclear what Egyptian authorities will do to comply with the court's decision, but it appears to fall in line with a recent push to put a stop to the tunnels.
Egyptian security forces began sending sewage through the tunnels earlier this month as part of a new campaign to flood them, two senior intelligence sources said.
The sources, who asked not to be identified because they were not authorized to speak to the media, said security forces were using the new tactic as part of a stepped-up effort to stop smuggling.
There are hundreds of underground tunnels -- big and small -- in the vast Sinai Desert area.
In Israel, authorities have accused Hamas of using the tunnels to smuggle missiles and other weapons used in militant attacks.
And in Egypt, authorities have blamed the tunnels for violence in the Sinai Peninsula.
Tuesday's Cairo administrative court decision requires the Egyptian government to close and demolish what it described as "illegal secret tunnels," the state-run EgyNews agency reported.
After a surge of violent attacks in the Sinai Peninsula in August, Egypt's interior minister blamed the tunnels, citing them as smuggling routes for terrorists and weapons.
Bulldozers and cranes were sent to block the tunnels on the Egyptian side as Egypt's military leadership accused dozens of militants from terrorist factions in Gaza of carrying out a deadly attack on soldiers near the Rafah border crossing.
But smuggling through the tunnels has continued, with goods like cement, sugar and clothes slipping through.
U.S. and Israeli officials say that Iran has used the tunnels to send arms and missile parts into Gaza.
In December, then-U.S. Secretary of State Hillary Clinton called on Egypt to crack down on arms smuggling through the tunnels, saying they were being used to send weapons from Libya and Sudan to militants in Gaza.
"I am concerned that, if more rockets are allowed to enter Gaza through the tunnels, that will pave the way to more fighting again soon," she said.
In November, one of the most powerful tribal figures in northern Sinai told CNN that it was likely that long-range missiles had been smuggled through the tunnels "most likely hidden among other merchandise that is loaded onto big trucks that go through the big tunnels."
Ibrahim Menai, who reportedly owns several of the smuggling tunnels that connect Sinai with Gaza, said Bedouin smugglers got weapons from Sudan by sea on small fishing boats and by land through rugged mountain terrain.
"The weapons that are smuggled to Gaza are mostly Grad missiles, anti-aircraft missiles, and recently during the Libyan revolution, advanced shoulder-held anti-tank missiles came through," Menai said.
In Gaza, the recent Egyptian campaign to flood the tunnels with sewage has sparked concern about rising prices of goods, worries about the crippling of a vital economic element and criticism that the Egyptian government is helping Israel.
The tunnels have surged in importance since Israel imposed a blockade on Gaza in 2007 after Hamas seized control of the Palestinian territory.
CNN's Tim Lister, Mohamed Fadel Fahmy, Barbara Starr, Diana Magnay and Bryony Jones and journalist Talal Abu Rahm contributed to this report.