Sixteen people were injured in a bomb explosion at a metro train in Cairo Thursday as gunmen killed five Egyptian soldiers and policemen in two separate attacks in northern Sinai.

According to Health ministry official Ahmad Al-Ansari, all 16 people were injured in a stampede caused by the explosion.

Metro authority spokesman Ahmed Abdel Hady said the bomb had been placed inside a bag, leading to panic on the train during rush hour.

Since the military overthrew Islamist president Mohamed Morsi in July last year, Egypt has been hit by a wave of attacks.

In a separate attack Thursday in Rafah, bordering the Gaza Strip, gunmen stopped a car carrying two police conscripts and killed them.

On the same day, three soldiers on leave were travelling in a taxi near Sheikh Zuweid when they were ambushed and shot dead.

Security and medical sources said the gunmen that shot the soldiers and policemen were unidentified.

Last month, the army declared a three-month state of emergency in the Sinai area after two attacks left 33 security personnel dead.

The Egyptian military said one of its navy vessels came under terrorist attack in the Mediterranean Wednesday. Five servicemen were injured and eight others are still missing at sea.

Just last week, four people were killed on a train north of the capital from a bomb explosion. Bomb blasts in the Cairo metro and near a presidential palace injured several other people.

An Islamist militant insurgency killed many policemen and soldiers. Egpyt is fighting to combat the attacks but a maritime attack is unprecedented.

The Sinai-based jihadist group Ansar Beit al-Maqdis have claimed many of the previous attacks. The group pledged its allegiance to the Islamic State this week.

IS has seized territory in Syria and Iraq.