In an unprecedented move, Hamas asked Cairo to shut smuggling tunnels along a section of the Gaza-Egypt border near the site of Sunday’s attack on the Kerem Shalom crossing and suggested a joint border protection force, Lebanese media reported on Saturday.

Hamas had reportedly suggested the formation of an Egyptian-trained force “to defend the border and prevent incidents which would harm the national security of Egypt or Gaza” before Sunday’s terrorist attack. Hamas sources told Al Akhbar that the Islamist group warned Egypt of terrorist elements who would not refrain from criminal activity to sabotage relations between Cairo and the Palestinian enclave.

The Hamas source also reported that the Islamist terrorist group is struggling to close down smuggling tunnels along the stretch of the border southeast of Rafah because of its proximity with the Israeli border fence.

Hamas began sealing off tunnels between the Gaza Strip and Egypt after Sunday’s terrorist attack.

Hamas’s call for assistance follows an Egyptian crackdown launched earlier this week to destroy the elaborate network of underground tunnels used to smuggle weapons, terrorists and goods between Sinai and Gaza. Over 150 have reportedly been destroyed.

Egypt also closed the Rafah border crossing with the Gaza Strip and has arrested Palestinian crossing illegally to Egypt through tunnels. Authorities arrested three Gazan brothers Friday night who had crossed into the Sinai through smuggling tunnels, Maan News reported.

Egyptian officials claimed that perpetrators of the Kerem Shalom attack entered the Sinai Peninsula from the Gaza Strip via such tunnels.

Smuggling under the 15 kilometer (9 mile) border has circumvented official crossings and bypassed restrictions for many years. Al Akhbar’s report cited economist Omar Shaban’s valuation of trade passing through tunnels into the Gaza Strip as approximately $500 million per annum.

The report also quoted Hamas’s Deputy Politburo Chief Musa Abu-Marzuq reiterating his organization’s denial of any Gazan involvement in the attack on Kerem Shalom and Rafah on Sunday in which 16 Egyptian soldiers were killed before the attackers smashed across the border into Israel in a stolen Egyptian APV and were blown up by the Israel Air Force. Egypt has demanded the extradition of several Islamists suspected of orchestrating the attack.