CAIRO (Reuters) - Sixteen militants have been killed and 34 people arrested in a major security operation, Egypt’s military said on Sunday, part of a campaign to crush Islamist insurgents blamed for a string of attacks.

Sixty-six targets, arms depots, SUVs and motorbikes used by militants were destroyed in raids focused mainly in Sinai, but also in the Nile Delta and the western desert, the army added in a statement carried on state TV.

President Abdel Fattah al-Sisi, who is seeking re-election in March, ordered the armed forces in November to defeat militants within three months after an attack on a mosque killed more than 300 people, the deadliest such incident in the Arab world’s most populous country.

Islamist insurgents have been targeting security forces since 2013 when the army, then led by Sisi as army chief, ousted President Mohamed Mursi of the Muslim Brotherhood following mass protests against his rule.

The security operation launched on Friday involves troops from the Egyptian air force, navy and army as well as the police and border guards.

“The air force targeted and destroyed 66 targets used by terrorist elements to hide from air and artillery attacks, and to escape from their bases during raids,” the statement said.

A total of 16 militants were killed, it said, and four militants were captured. Thirty other people suspected of links to militants were also detained for questioning, the statement said.

Medical sources said Ismailia General Hospital early on Sunday received the bodies of 10 militants killed in Sinai and that DNA samples were taken to identify them.

A video recording posted on social media, purportedly from a group affiliated to Islamic State, appeared to showed masked militants executing soldiers and civilians they accused of collaborating with security forces.

A member of Wilayat Sinai warned Egyptians against voting in a presidential election, scheduled next month, and urged Islamist militants to “destroy their day of polytheism, spill their blood, beginning with their leaders”.

The authenticity and date of the 23-minute video could not immediately be verified, but a reference to an Egyptian military statement on Friday suggested that at least part of it was completed after the security operation began.

The military statement earlier on Sunday said forces involved in the operation had found a media center with computers, communication equipment and books and documents related to jihadist ideology.

Security forces also uncovered and destroyed six farms used to grow banned narcotics, the statement said.