GAZA CITY (Ma’an) -- Just 10 percent of the tunnels under Gaza's border with Sinai are still in operation, after Egypt moved to close the underground network in recent weeks, tunnel owners said Friday.

The tunnel trade, which operates with oversight from the Hamas government in Gaza, is now placed under strict regulations, they told Ma'an.

Both Egyptian and Palestinian authorities are insisting on clear identification of people using the tunnels for passage, as well as regulating the quality of goods passing through, one owner, who gave his name as Mahmoud, told Ma'an.

The operation of the tunnels depends on the security situation in Gaza and Egypt's Sinai, he added.

When security conditions permit, fuel and construction materials are allowed to freely pass into Gaza, Mahmoud said.

Last week, Gaza's ministry of national economy said monthly imports of basic foodstuffs had fallen 31 percent and construction materials had declined by 45 percent since the tunnel closures.

Meanwhile, a security official in the Gaza strip told Ma’an that tunnels were operating again, after being closed for two hours early Friday amid clashes between militants and security officers in Sinai.

Eyewitness told Ma’an that Egyptian bulldozers remained on the Egyptian borders with the Gaza strip, and were continuing work to destroy the tunnels.

The Gaza Strip is under an Israeli land and sea blockade, and its sole border crossing not controlled by Israel, Egypt's Rafah terminal, is not equipped for the passage of goods.

To circumvent the blockade, a vast underground tunnel network into Egypt was established, with the oversight of the Hamas-run government.

After years of turning a blind eye, Egypt started closing the tunnels after the Aug. 5 attack in Sinai when gunmen killed 16 Egyptian soldiers. Egypt suspects the tunnels were used by some of the militants, while Hamas says no-one from Gaza was involved in the attack.