A rush-hour car bomb attack targeting a bus carrying riot police killed 11 people and wounded 36 others Tuesday, Istanbul's governor said.

Speaking at the scene of the blast in the district of Beyazit, Istanbul Governor Vasip Sahin said the dead included seven police officers and four civilians. At least three of the wounded were in serious condition, abc news reported on Tuesday.

The explosion was caused by a bomb placed inside a car and was detonated as the police vehicle was passing by, Sahin said.

The police bus was overturned from the force of the blast which also damaged nearby buildings, including a hotel whose entrance appeared gutted and windows were blown out. The hotel however, was closed and had no guests. Several cars were also wrecked.

The blast occurred on a busy intersection near an Istanbul University building, forcing officials to cancel exams.

Foreign Minister Mevlut Cavusoglu condemned the attack, which occurred on the second day of the holy Muslim month of Ramadan.

"They are cold-heartedly exploding bombs on a Ramadan day," Cavusoglu said in a television interview.

Prime Minister Binali Yildirim was meeting with the country's interior minister to discuss the attack.

There was no immediate responsibility claim and Sahin would not comment on who may be behind the attack.

Tuesday's attack was the fourth major bombing in Istanbul this year. Two of them targeting tourists and two hitting security forces. The spike in violence has led to a sharp dip in tourism, a mainstay of the economy.

Source ; MENA