ISTANBUL (Reuters) - Turkish authorities have stepped up security across Istanbul, CNN Turk and other local media reported on Thursday, a day after France said it was closing its diplomatic missions in both Istanbul and the capital Ankara over security fears.
Turkey is on high alert after a series of deadly bomb attacks this year, some claimed by Kurdish militants and others blamed on Islamic State. A triple suicide bombing at Istanbul's main airport last month killed 45 people.
Police were individually checking all passengers before allowing them to ride the Marmaray railway that runs under the Bosphorus strait connecting the European and Asian sides of Istanbul, CNN Turk and the Hurriyet newspaper reported.
No one was immediately available to comment at the Istanbul governor's office. Earlier this month, Prime Minister Binali Yildirim said heavily armed special forces had been deployed on the Marmaray, as well as at the airport and train stations. However, it is rare to see police checking individual passengers and their bags on Istanbul's commuter trains.
Photos posted on social media on Wednesday showed special force members patrolling Istanbul's Istiklal street, a popular shopping area for locals and tourists. Three Israeli tourists and one Iranian were killed in March when a suspected Islamic State bomber blew himself up on Istiklal.
France shut its diplomatic missions in Turkey's two main cities until further notice on Wednesday and cancelled planned events to mark its July 14 National Day due to security concerns.
It also said there was information suggesting a "serious threat against plans for celebration of the July 14 national holiday in Turkey".
Turkey is grappling with multiple security threats. It is a member of the U.S.-led coalition against Islamic State militants in Syria and is fighting a Kurdish insurgency in its mainly Kurdish southeast.
(Reporting by Ece Toksabay and Ayla Jean Yackley; writing by David Dolan; editing by Mark Heinrich)