CAIRO (AP) -- Smoke billowed in the sky as Egyptian helicopter gunships rocketed suspected Islamic militant hideouts in the lawless northern Sinai Peninsula for a second day on Sunday, killing 11 suspected fighters as part of the largest military offensive in the region in years, military officials said.
They say the assault aims to drive out al-Qaida inspired groups from several villages of the restive border region, where militants have established strongholds and stockpiled an unprecedented amount of weapons.
Also Sunday, a militant group in northern Sinai allegedly claimed responsibility for a failed assassination attempt on the country's interior minister last week. In a statement attributed to Ansar Jerusalem posted on militant websites, the Islamic extremist group claimed it was behind the attack on Mohammed Ibrahim. The statement says military chief Gen. Abdel-Fattah el-Sissi, who led a coup against former Islamist President Mohammed Morsi, is another target.
A military official said 11 militants and one soldier were killed in the fighting on Sunday. He said 10 militants had been arrested. A day earlier two soldiers and nine militants were killed in the offensive. The official spoke anonymously because he was not authorized to release the information.
Gen. Osama Askar of the 3rd Army told reporters troops had seized at least 10 shoulder-fired Sam-7 anti-aircraft missiles a day earlier. They were found in a mosque and in homes of suspected militants in the town of Sheikh Zuweyid, near the border with the Gaza Strip and Israel.
Western officials say thousands of shoulder-launched missiles went missing from Libyan arsenals since that country's 2011 civil war. Egyptian authorities say Libyan missiles have been smuggled into the Sinai, and some of those have gone on through underground tunnels to Gaza.
Sunday's airstrikes targeted the villages of el-Mahdiya and el-Moqataa on the outskirts of Rafah and Sheikh Zuweyid. One official said U.S.-made Apache helicopters hit shacks, houses, olive farms and cars used by militants.
The strikes paved the way for a ground offensive, allowing troops backed by armored vehicles to sweep homes of suspected militants.
Armed Forces spokesman Col. Ahmed Mohammed Ali said that helicopters had provided air cover for what was "the biggest security operation" in the northern Sinai in years. Ali's statement, posted on his official Facebook page, also said that 118 houses and farms used as hideouts had been demolished in the operation by Saturday.
A second military official in Cairo told The Associated Press that the military found heavy weapons, explosive belts for suicide bombers, mortars, RPGs, anti-aircraft missiles and maps with positions of the military in the region.
Residents witnessed columns of trucks and armored vehicles pouring into the area over the weekend. Some said they hadn't seen foot soldiers in their villages in decades. Communications were jammed for hours, as authorities seized control of two telephone exchanges. All roads leading up to the northern region of the peninsula have been sealed off and troops have encircled a dozen villages. Some local tribal leaders have expressed relief over the operation, but others remain skeptical, saying innocent men have been arrested arbitrarily.
Over the past weeks, the military has also bulldozed homes along the Gaza border and caved in tunnels beneath them in preparations for creating a buffer zone to reduce weapon smuggling and militant crossings.
Officials say militants are believed to be responsible for a series of attacks in a region they overran after the fall of autocrat Hosni Mubarak in 2011. The region has seen a spike in attacks since the Morsi's overthrow on July 3. The Cairo-based military official accused Morsi of giving militants free reign to stockpile weaponry by making deals with them to cease attacks when he was in office in return for amnesty and a halt of military action against them.
The militants, officials say, belong to a number of extremist groups that seek the establishment of an Islamic Caliphate in the northern Sinai based on a narrow and hard-line interpretation of the religion. The officials spoke on condition of anonymity because they were not authorized to speak to the press.
The groups reject the ideologies of Morsi's Muslim Brotherhood group as too moderate and view their participation in elections as heresy. They have said their goal is to drive out the authority of the central government, not to restore Morsi to power.
The alleged statement by Ansar Jerusalem, known in Arabic as Ansar Beyt el-Maqdis, said the group will "avenge" the deaths of Muslims by the interior and defense ministers' forces, which have killed more than 100 militants in Sinai since Morsi was toppled. The country's security forces also raided two pro-Morsi protest camps in Cairo in mid-August that sparked several days of violence that killed more than 1,000 people, most of them Islamist supporters of the Brotherhood.