The Egyptian army is demolishing buildings deemed a security threat in the Sinai Peninsula, close to the border with the Gaza Strip, the army said.
Ahmed Ali, an Egyptian army spokesman, said on Sunday that the move was geared to consolidate security in the border region, where he said the military had discovered a network of booby traps.
"There is cooperation between the armed terror groups with their counterparts in the Gaza Strip, and more than one joint operation has been monitored," Ali said.
The army was "dealing" with any building deemed a security threat in a corridor stretching from 500 metres to 1km from the Gaza frontier, he said.
He was speaking during a news conference in Cairo to present the army's progress since it stepped up operations against armed groups in Sinai last week.
Fighters have intensified attacks in Sinai since July, when the army deposed President Mohamed Morsi of the Muslim Brotherhood, who have links to Hamas.
Attacks on security forces are now occurring almost daily. Authorities say attacks have killed more than 100 policemen and soldiers in recent months.
The army has used tanks and military gunships in its offensive against the fighters.
Ali said troops have arrested 309 suspects, including Palestinians, in operations that began in the region in July.
Egyptian state media last week reported that Hamas, which governs the Gaza Strip, had been involved in teaching fighters in Egypt how to plant bombs and that it had given them landmines - an accusation dismissed by the Palestinian group as an attempt to demonise it.
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, the Qassam brigades, had been found in the security sweep.
The army seized weapons including anti-aircraft missiles, he said. Motorised paragliders had also been found, which he said showed an effort to develop new methods of attack.
In the last 48 hours, Ali said, troops had discovered explosives laid in tunnels along the border and under Egyptian watchtowers, with detonating wires running back into Gaza.
Hamas government spokesman Ihab al-Ghussein denied fighters were using the Palestinian territory as a staging ground for operations against Egypt.
"We deny any connection between Gaza, its resistance and government, and the tunnels and the explosives which were mentioned by the Egyptian army spokesman today," al-Ghussein told reporters.
Meanwhile, an Egyptian journalist appeared before a military court on Sunday, accused of spreading lies about the army's campaign against fighters in Sinai.
The court in the Suez canal city of Ismailiya adjourned Ahmed Abu Deraa's hearing to September 18.
Abu Deraa, who writes for the independent daily Al-Masry Al-Youm, was detained on September 4 in north Sinai over published reports that army raids had hit a mosque and houses and also injured civilians.
Authorities say they are targeting "terrorists" in the peninsula that borders the Gaza Strip and Israel.
Media watchdog Reporters Without Borders and rights activists have condemned Abu Deraa's detention.
But the military spokesman justified the journalist's detention and military trial.
"Investigations showed that Mr Abu Deraa spread lies, saying that the Egyptian armed forces were attacking mosques, women and children.
"He deliberately spread false news," Ali told reporters.
Few journalists have direct access to what is happening in Sinai because of security restrictions and concerns.