The Egyptian army has destroyed 152 tunnels on the Egypt-Gaza border since the end of July, an army spokesman said Sunday.

Ahmed Ali, the spokesman, said the Egyptian army demolished buildings constituting a security threat up to a kilometer from the border. He added that Gaza-based groups were carrying out operations together with armed Islamists in the Sinai Peninsula.

Ali said the demolitions have not established a buffer zone that Hamas fears Egypt is creating along the border to further isolate Gaza, whose economy is propped up by smuggling through tunnels to Sinai. He was speaking during a news conference in Cairo to present the army’s progress since it stepped up operations against Islamist militants in Sinai last week.

The army seized weapons including anti-aircraft missiles, he said. Motorized paragliders had also been found, which he said showed an effort to develop new methods of attack.

Ali said the army was “dealing” with any building between 500 meters and one kilometer from the Gaza border that is considered a possible security threat. He said houses concealing tunnels used for weapons smuggling were a threat to Egypt’s national security.

Ali did not state the number of armed activists killed in the Sinai operation but said that 309 were arrested, adding that 100 Egyptian soldiers were killed and 140 wounded since the toppling of Mohammed Morsi's government.

Ali declined to accuse Hamas directly of attacks in Egypt, though he said hand grenades stamped with the name of the Palestinian group’s armed wing, Iz al-Din al-Qassam, had been found in the security sweep.

"There is cooperation between armed terror groups and their counterparts in the Gaza Strip," Ali said, adding that on Friday security forces discovered two bombs under a military observation post, with wires leading through a tunnel to the Gaza Strip. "The explosives were to be detonated in Gaza," Ali said.