At least three people were killed and 17 others injured early Monday in a mistaken attack on a bus in Egypt's North Sinai, a security source told Xinhua.

The source said the assailants intended to attack an armored security vehicle but their rocket-propelled grenades missed and instead hit the bus, which was carrying cement company workers.

"There are Palestinian elements involved in the attack," the security source said on condition of anonymity, noting that the raid took place in an area close to the border with Israel.

At least 10 people, including civilians and security personnel, have been killed in attacks by extremists in Sinai in the past week, the official MENA news agency reported.

The news agency added that the armed forces have since June 30 killed 37 militants in a large-scale security operation aimed at combing the peninsula.

A group of militants last week bombed a pipeline in North Sinai that transports natural gas to Jordan.

The recurrent attacks came after the Egyptian army ousted President Mohamed Morsi early this month amid calls from millions of protesters for his removal due to his "maladministration."

The Muslim Brotherhood, which propelled Morsi to power a year ago, has condemned his ouster as a military coup aimed at undermining the rising influence of Islamists. It has called for massive protests to escalate pressure on the military.