About 20 members of the security forces had also been injured when more than 100 militants repeatedly attacked security outposts south of the border town of Sheikh Zuweid
At least 24 militants, six soldiers killed in attacks in Egypt's Sinai
At least 24 militants and six soldiers were killed on Sunday in attacks on military outposts in North Sinai, the Egyptian military said in a statement.
The statement did not give details, but security and medical sources said about 20 members of the security forces had also been injured when more than 100 militants repeatedly attacked security outposts south of the border town of Sheikh Zuweid.
The attackers used car bombs and rocket propelled grenades (RPG), the sources said. The militants also clashed with the security forces using light weapons, the sources added.
ISIL claimed responsibility for the attacks.
Islamic state has claimed responsibility for two rockets fired on Sunday from Egypt'sSinai peninsula into Israel, an official statement by the group said on Monday.
"The fighters confronted Israeli jets that flew above the state and targeted the Eshkol compound with two Grad rockets," ISIL said in a statement on Monday.
Air raid sirens went off in a part of southern Israel and the Israeli military said two rockets were fired from Sinai at Israel. There were no immediate reports of damage or injuries.
On Friday, the militant group claimed an attack on security forces in the peninsula that killed at least six soldiers.
Egypt is fighting an insurgency by militants affiliated with ISIL in the Sinai Peninsula, where hundreds of soldiers and police have been killed since 2013, when the military ousted Islamist president Mohamed Mursi after mass protests.
The militants have also extended their campaign to other parts of Egypt, most recently attacking churches in Cairo and other cities with the loss of dozens of lives.