CAIRO (AP) — Egypt's military has destroyed dozens of targets, killed 16 militants and detained over 30 suspects as part of its latest operation against Islamic militants in the restive northern Sinai Peninsula, the army said on Sunday.

Spokesman Col. Tamer el-Rifai said that airstrikes hit vehicles, weapons caches, communications centers and illegal opium fields in the sweep, which began on Friday and comes as a response to a pickup in extremist violence in Egypt.

"The air force targeted and destroyed 66 targets used by terrorist elements to hide from air and artillery attacks," for shelter during raids by security forces, he said in a statement. With North Sinai closed off for non-residents and journalists, the army's casualty figures could not be independently confirmed. Telephone connections to the area, both mobile and landlines, are often shut down as well.

The operation, which targets "terrorist and criminal elements and organizations," involves land, naval and air forces from the army and police, and covers north and central Sinai, the Nile Delta and the Western Desert along the porous border with Libya.

The offensive comes ahead of a March vote that will undoubtedly see President Abdel-Fattah el-Sissi win a second four-year term, after all serious opponents have been sidelined or driven out of the race.

El-Sissi, who has waged one of the most sweeping crackdowns on dissent in Egypt's modern history, says he is the only one who can restore Egypt's security, and ordered the Sinai operation after militants struck.

In November, extremists killed 311 worshippers in a mosque attack in north Sinai, the deadliest such killing in Egypt's modern history, prompting el-Sissi to give security forces a three-month deadline to restore order using "all brute force" required.

But the militants launched another brazen attack in December, firing a missile at a helicopter that was part of the entourage of Egypt's defense and interior ministers, who were in the provincial capital el-Arish on an unannounced visit. Neither minister was in the aircraft when the attack took place but the missile killed an officer and wounded two others.

Militancy has long been a problem in Sinai, but it spiked dramatically after el-Sissi led the military's 2013 overthrow of elected but divisive Islamist President Mohammed Morsi. Violence has been concentrated in north Sinai, but has also spread to the mainland.

Meanwhile, two militant groups that have carried out previous attacks on security forces denounced the new operation in statements posted online.

The group known as Hasm urged Egyptians to unite against the "traitorous regime" which was "digging its own grave" by "declaring open war on Sinai."

Another group, called Liwaa el-Thawra, said the offensive, involving tens of thousands of troops, was a sign the government was losing control of Sinai, where it vowed to continue it struggle.

Authorities believe both groups, which have been designated as terrorist organizations by Egypt and the United States, to be splinter groups of Morsi's outlawed Muslim Brotherhood.

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Associated Press writer Maamoun Youssef in Cairo contributed to this report.