ISMAILIA- Islamic State insurgents attacked several military checkpoints in Egypt's North Sinai on Wednesday in a co-ordinated assault that killed more than 100 people - one of the biggest militant strikes in Egypt's modern history.
Soldiers, policemen, civilians and militants were among the dead.
Islamic State's Egyptian affiliate, Sinai Province, claimed responsibility and said that it had attacked more than 15 security sites and carried out three suicide bombings.
Egypt's armed forces said that at least 100 militants and 17 soldiers had been killed.
One security source said about 300 militants, armed with heavy weapons and anti-aircraft weaponry, had taken part in the attacks while the army said five checkpoints were hit and the fighting had raged for more than eight hours.
The assault - a significant escalation in violence in the Sinai Peninsula that lies between Israel, the Gaza Strip and the Suez Canal - was the second high-profile attack in Egypt this week. On Monday, a bomb killed the prosecutor-general in Cairo.
The insurgents, who have killed hundreds of policemen and soldiers, want to topple the Cairo government and have stepped up their campaign since 2013, when then-army chief Abdel Fattah al-Sisi removed President Mohamed Mursi of the Muslim Brotherhood after mass protests against his rule.
Sisi, who regards the Brotherhood as a threat to national security, has since overseen a harsh crackdown on Islamists.
Security sources said the militants had planned to lay siege to the town of Sheikh Zuweid.
"But we have dealt with them and broke the siege on Sheikh Zuweid," one of the sources said.
Army F-16 jets and Apache helicopters strafed the region. Soldiers had destroyed three SUVs fitted with anti-aircraft guns, the army said.