Turkish police arrest four suspects for yesterday’s Istanbul bombing

The four were arrested hours after Tuesday's attack which killed 11 and injured 36 people.

The detainees were being held at Istanbul's main police headquarters, Turkish state media reported. 

Speaking at the scene of the blast in the Beyazit district, Istanbul Governer Vasip Sahin said a bomb placed inside a car detonated as the police bus passed by, killing seven members of the police force as well as four civilians. 

Reports said the explosion took place near the Vezneciler metro station, which is within walking distance of some of the city's main tourist sites, including the Suleymaniye Mosque.

Turkish president Tayyip Erdogan said on Tuesday the country's fight against armed groups will continue "to the end."

Speaking to reporters after visiting some of the injured in a hospital near the site of the blast, Erdogan said the attack was "unforgivable".

Istanbul had already been hit by two bombings this year, including in tourist areas. Both attacks were blamed on Daesh.

A pair of attacks in Ankara were claimed by Kurdish separatists and killed dozens.

The attacks have had a dire effect on the tourism industry heading into the key summer season.

According to the latest release by the tourism ministry some 1.75 million foreigners came to Turkey in April, down more than 28% on April 2015,