A police sergeant was killed in Al-Arish on Wednesday, one day after another attack, also in North Sinai, left 11 security personnel dead. Ministry of Interior spokesman Hany Abdel Latif said the attack occurred just outside the sergeant's house. "We are still looking into the circumstances surrounding the attack," he added. On Tuesday, an attack on a security convoy in North Sinai left one officer and ten conscripts dead, after it hit a landmine. The perpetrators of the attack are still unknown. Three militants were killed on Monday during clashes with the armed forces in Sheikh Zuweid city, reported state-run news agency MENA. On 28 June, unidentified gunmen stopped a bus transporting police officers and shot four of them dead nearby Al-Arish. Since the ouster of President Mohamed Morsi, armed groups have been targeting security personnel, especially in the North Sinai region. A Ministry of Foreign Affairs factsheet places the death toll for terrorist activities since January 2011 to April 2014 at 971, including 477 policemen and 187 army personnel. While previous attacks mainly targeted working security forces on duty, there has been a trend in recent months, in which off-duty police officers are killed. More than a dozen police officers have been killed in drive-by attacks in the Nile Delta governorate of Sharqeya alone. Almost all of these attacks were perpetrated by armed men on motorcycles, striking police officers on their way home from work. Ansar Beit Al-Maqdis, an Al-Qaeda-inspired militant organisation based in Sinai, has claimed the majority of violent attacks against police and army forces.