EL-ARISH, Egypt (AP) -- Egyptian military aircraft pounded suspected positions of al-Qaida-inspired fighters in the Sinai Peninsula, killing 13 people, officials said Friday, as fears rise over an increasingly well-armed insurgency that is striking with increasing regularity in the capital. In the latest attack, bombs on a highway on Cairo's outskirts hit a police truck.
At the same time, protests by Islamist supporters of ousted President Mohammed Morsi brought further violence, with clashes in several provinces.
In an eastern Cairo district, an attempt by pro-Morsi protesters to commemorate dozens killed in clashes a week ago turned into new battles with police and pro-military civilians that authorities said involved fire by automatic weapons. The Islamist protesters had tried to set up a stage in Naam Square, blocks from the fighting last Saturday, when civilians descended on them, firing birdshot and throwing stones, participants in the protest said.
Islamists have been protesting nearly daily for months demanding the reinstatement of Morsi, and have been met with a heavy crackdown that has killed hundreds and led to the arrests of thousands since army chief Abdel-Fattah el-Sissi removed the president on July 3. The deaths have brought a new tone from protesters -- one increasingly demanding vengeance.
"The demands in the first months after Morsi ouster was his reinstatement," said Hassan Farahat, one of the protesters at Naam Square. "But after all the massacres, the demand now is retribution and the execution of el-Sissi."
The military-backed government accuses Morsi's Muslim Brotherhood of orchestrating violence by Islamic militants and has officially declared the group a terrorist organization. The Brotherhood denies the accusation, calling it a pretext for authorities to crush it.
Since Morsi's ouster, which followed giant nationwide protests demanding his removal, Sinai-based militants have stepped up a campaign of bombings, suicide attacks and shootings against police and soldiers, along with assassinations of senior security officials. Last Saturday, militants downed a military helicopter in the northern Sinai, killing all five crewmembers.
The al-Qaida-inspired group that has claimed responsibility for most of the previous attacks --Ansar Beit al-Maqdis, or Champions of Jerusalem -- said it downed the aircraft, posting a video of a fighter hitting a helicopter with a shoulder-fired missile. The video suggested the group has gained access to more sophisticated weaponry.
Military officials said investigations have found that two Egyptians and four Palestinians were involved in the downing. The officials spoke on condition of anonymity because they were not allowed to talk to the press. Authorities have long accused militants from Gaza of involvement in the Sinai violence.
Overnight, explosions resounded for miles in the Sinai town of Sheikh Zuweyid, near the border with the Gaza Strip, as Apache helicopters fired dozens of missiles, witnesses said. The military officials said the strikes targeted houses, shops, vehicles and other gathering points suspected of being used by militants.
Military spokesman Ahmed Mohammed Ali said 13 suspected militants were killed. The deaths brought to 20 the number of militants killed the past week, one of the highest tolls since the military stepped up operations after Morsi's ouster.
Ali said those killed in the overnight strikes were "extremely dangerous takfiri elements who are loyal to the Brotherhood terrorist group." Takfiri is a term in Arabic referring to Islamic radicals.
In its latest statement Thursday, Ansar Beit al-Maqdis claimed responsibility for the assassination Tuesday of a senior police officer in Cairo.
Maj. Gen. Mohammed el-Said was shot to death as he left his home in the Haram district, a neighborhood near the Pyramids. He was an aide to the interior minister and head of the technical office in the Interior Ministry, which is in charge of police.
In its statement posted on militant websites, Ansar denounced el-Said as "a renegade criminal" and warned of more attacks. "Expect the worst, as the time of punishment is near," it said.
Separately, the group said it blew up a natural gas pipeline on Monday night outside el-Arish, the provincial capital of North Sinai. Pipelines have repeatedly come under attacks since the 2011 anti-Mubarak uprising and the security vacuum that ensued.
Earlier Friday, two planted explosive devices detonated on a main highway on the western outskirts of Cairo, hitting a passing vehicle carrying riot police and wounding an officer, Interior Ministry spokesman Hani Abdel-Latif said.
Nearby, security forces shot dead a minibus driver at a police checkpoint in the Sixth of October suburb of the capital. The police said the driver was trying to ram the checkpoint, ignoring warning shots, the ministry said. The driver was killed, one passenger wounded, and three others were arrested it said, adding that the incident was under investigation.