North Sinai clashes ongoing, death toll rises to at least 50. (AlAhram).
14:00: Militants are trying to storm the besieged Sheikh Zuweid police station, according to several news websites.
13:55: Fifty Egyptain soldiers killed so far, security sources tell Reuters.
13:45: Israel closes Nitzana and Kerem Shalom border crossings amid ongoing clashes in North Sinai, Sky News Arabia reports.
13:35: Armed forces spokesperson Brigadier General Mohamed Samir says clashes with militants are ongoing. Seventeen militants have been killed so far.
The death toll of soldiers and militants is expected to rise.
This is the second official statement issued by the Egyptian armed forces about the on-going clashes in Sinai. 13:30: Security sources say the death toll of security personnel in Sheikh Zuweid is at least 20, with 30 injured.
Health sources say Al-Arish Military Hospital has received the body of an army officer who was killed during the attack on El-Rafai checkpoint. He is reportedly Lieutenant Mohamed Ashraf Hussein. At least 20 Egyptian policemen and soldiers have been killed and 30 wounded in ongoing clashes with IS-affiliated militants in North Sinai on Wednesday, an official source said, marking the first major attack in the restive peninsula in five months.
The security source, who preferred to remain anonymous until an official statement is issued, said 38 armed men have also been killed in the clashes that continue in the city of Sheikh Zuweid, according to Ahram's Arabic news website.
Islamic State-affiliated Sinai Province, previously known as Ansar Beit Al-Maqdis, has claimed responsibility for the attacks in a statement.
The IS group said that its allies had mounted 15 simultaneous attacks on military sites, including "martyrdom operations" on Al-Arish's officers club and two checkpoints in Sheikh Zuweid.
Eleven checkpoints and a police station in Sheikh Zuweid were attacked by militants using missiles, the statement added. Al-Ahram's correspondent in North Sinai reported that a local woman and her 15-year-old daughter have been killed, and five people from a single family injured in the on-going clashes.
Another security source said militants have occupied the rooftops of houses in Sheikh Zuweid after forcing the occupants to flee. Militants have planted IEDs on local highways to hinder the advance of Egyptian troops, he added.
On Wednesday morning, around 70 militants fired mortar rounds and used a car bomb in separate attacks on five checkpoints in the town of Sheikh Zuweid, according to security sources.
"Egyptian armed forces returned fire, killing at least 22 terrorists and destroying three vehicles armed with anti-craft missiles," army spokesman Brigadier-General Mohamed Samir said in a statement.
There is currently a power cut in Sheikh Zuweid and local residents are staying in their houses due to the on-going fighting between militants and security forces, according to eye witnesses.
This is the second major attack of its kind against security forces in North Sinai this year. Read the live updates here. Live tweets can be read here.
Series Of Deadly Terrorist Attacks In #Egypt's #Sinai Peninsula, @Maplecroft_GAD Map - pic.twitter.com/7SbEQKHM4f— Terrormonitor.org (@Terror_Monitor) July 1, 2015
Related: 15 security sites raided simultaneously in North Sinai, says IS