A picture taken from the Rafah border of the southern Gaza Strip with Egypt shows smoke billowing in Egypt's North Sinai on July 2, 2015
Cairo (AFP) - Egypt on Thursday pressed its campaign to crush an escalating insurgency in Sinai, vowing to wipe out "dens of terror" on the peninsula after a spectacular attack by jihadists killed dozens.
The violence poses a major test for President Abdel Fattah al-Sisi, the former army chief who has pledged to eliminate the militants.
The military deployed F-16 warplanes on Wednesday to bomb the Islamic State fighters who battled security forces on the streets of the North Sinai town of Sheikh Zuweid after launching a surprise dawn blitz on army checkpoints.
It said 17 soldiers and 100 militants had been killed, but medical and security officials said the death toll was at least 70 people, mostly soldiers. Dozens of jihadists also died.
On Thursday the military carried out search operations around Sheikh Zuweid, security officials said.
The head of security in North Sinai, General Ali al-Azazi, told AFP that security forces were "mobilised against the terrorists in Sheikh Zuweid".
Azazi said the ability of the jihadists to carry out new operations had been badly undermined because their huge losses both in men and weapons during Wednesday's confrontations.
The White House condemned the unprecedented wave of attacks, which came two days after state prosecutor Hisham Barakat was assassinated in a Cairo car bombing, the most senior government official killed in the jihadist insurgency.
The US National Security Council said it "will continue to assist Egypt in addressing these threats to its security".
Arab League chief Nabil al-Arabi urged the international community to "support the Egyptian government's efforts in fighting terrorist groups".
- 'Hamas gave support' -
A senior Israeli officer said the militant Palestinian group Hamas played a part in the attacks.
"In the latest attacks Hamas gave support with weapons and organisation to groups supporting IS," Major General Yoav Mordechai, said in an interview in Arabic with Al-Jazeera television.
There was no immediate comment from Cairo following the Israeli accusations but Egyptian authorities have in the past accused Hamas of backing jihadists in the Sinai .
The army says it has destroyed hundreds of tunnels used for smuggling supplies and arms between Sinai and Gaza, also used by militants to infiltrate Egypt.
State-owned newspapers rallied around Egypt's army, with Al-Akhbar newspaper calling for "Revenge" in its headline.
The military spokesman posted photographs on Facebook of militants killed in the fighting.
On Thursday gunmen on a motorbike shot dead a policeman in the town of Fayoum, south of Cairo, police said.
- 'Terrorists moved freely'-
The Sinai attacks were the most brazen in their scope since jihadists launched an insurgency in 2013 after the army, under Sisi's command, overthrew Islamist president Mohamed Morsi.
Militants took over rooftops and fired rocket-propelled grenades at a police station in Sheikh Zuweid after mining its exits to block reinforcements, a police colonel said.
"For hours the terrorists moved freely in the streets which they had mined," said Ayman Mohsen, a resident from Sheikh Zuweid who witnessed Wednesday's clashes.
"They fired rockets and bullets at the army camp in Zuhour and the Sheikh Zuweid police station."
"This is war," said a senior military officer. "It's unprecedented, in the number of terrorists involved and the type of weapons they are using."
The Islamic State group said its jihadists surrounded the police station after launching attacks on 15 checkpoints and security installations using suicide car bombers and rockets.
Troops regularly come under attack in the Sinai, where jihadists have killed hundreds of policemen and soldiers since Morsi's overthrow.
In April dozens of militants attacked checkpoints, killing 15 soldiers, and in January 25 people, most of them soldiers were killed in a rocket and car bomb attack on multiple police and army targets.
Analysts said the army lacked expertise in fighting the insurgents.
"It's not putting in the right units. The groups need to be chased by special forces and what the army is doing is that it is deploying regiments. Sending F-16s does not work," said Professor Mathieu Guidere, a specialist on jihadist groups at France's University of Toulouse.
Egypt responded to the growing insurgency on Wednesday by passing a controversial anti-terror law and requesting the appeals process be shortened, in measures it said would "achieve swift justice and revenge for our martyrs".