CAIRO, Sept 11 (Aswat Masriya) - Unknown gunmen shot one civilian dead in North Sinai's city of Sheikh Zuweid on Thursday, a security source said.

Three citizens were killed by militants in the past 24 hours, the source added.

One officer and 10 conscripts were killed last Tuesday in an attack on a security convoy in North Sinai.

Egypt's security forces have intensified their security measures in North Sinai in reaction to repeated militant attacks that target army and police officials, which rose significantly since the military ouster of former President Mohamed Mursi last year.

A fact-sheet prepared by Egypt's ministry of foreign affairs put the death toll for terrorism acts which took place since January 2011 and until April 2014 at 971, including 664 security personnel.