Twenty-seven killed in attacks in Egypt's North Sinai, Suez

Twenty-seven people were killed in four attacks in Egypt's North Sinai and Suez, security and medical sources said, in some of the worst anti-state violence in months and after commemorations around the anniversary of the 2011 uprising turned deadly this week.

Egypt's government faces an Islamist insurgency based in Sinai and growing discontent with what critics perceive as heavy handed security tactics.

Thursday's first attack was a bombing of military buildings in the capital of North Sinai province, that killed 25 and wounded at least 58, including 9 civilians, security and medical sources said.

The flagship government newspaper, al-Ahram, said its office in the town of Al-Arish, which is situated opposite a military hotel, headquarters and base that security sources said were the intended targets, had been "completely destroyed".

Later, suspected militants killed an army major and wounded six others at a checkpoint in Rafah, followed by a roadside bomb in Suez city that killed a police officer, and an assault on an army unit south of Al-Arish that wounded four soldiers, security sources said.

Sinai-based militants have killed hundreds of security officers since president Mohamed Mursi of the Muslim Brotherhood was removed from power following mass protests against his rule.

The military said in a statement on its Facebook page that the attacks were the result of a successful campaign to pressure the militants.

Tensions have risen across Egypt this week with protests, some of them violent, marking four years since the uprising that ousted longtime autocrat Hosni Mubarak from power.

Earlier on Thursday, a group of women protested in Cairo over the death of activist Shaimaa Sabbagh and around 25 others said to have been killed by security forces at rallies commemorating the 2011 uprising.

Sabbagh, 32, died on Saturday as riot police were breaking up a small, peaceful demonstration. Friends said she had been shot, and images of her bleeding body rippled out across social media, sparking outrage and condemnation.

"The Interior Ministry are thugs!" chanted around 100 womenprotesters at the site of Sabbagh's death. Some held up signs with the word "Murderer" scrawled over the face of Interior Minister Mohamed Ibrahim.

The protesters were defying a law that severely restricts protests. "People are here at incredible risk to themselves. But it's a way of standing against the fear they have instilled," said activist Yasmin el-Rifae.

Ibrahim has said an investigation into Sabbagh's death will lead to prosecution if any member of the security forces is found responsible.

One of the organisers of Thursday's demonstration said they had asked only women to attend because they feared infiltration by plainclothes male agents.

Across the street from the protesters, beside police officers, men stood making lewd gestures and yelling profanities. Others chanted in favour of President Abdel Fattah al-Sisi.

Criticism is growing of the security tactics Sisi has used since Mursi was ousted.

A crackdown that began with the deaths of hundreds of Brotherhood supporters and the imprisonment of thousands more has expanded to include liberals and other activists.

Some of those now on the wrong side of the government initially supported the protests that led to Mursi's removal and Sisi's rise to power, as people who knew Sabbagh said she had.