Dense fog cloaking the Bosporus Tuesday morning has prompted the cancellation of all ferry services in Istanbul.

Due to the stoppage of waterway service across the Bosporus, traffic is particularly crowded on the Marmaray, the metro which passes beneath the waterway, and the July 15 Martyrs Bridge.

In parts of Şişli, Beşiktaş, Sarıyer, Üsküdar, Beykoz, Fatih, Eyüpsultan and Beyoğlu districts, visibility was at 100 meters Tuesday morning.

Ferry services will reopen once visibility across the Bosporus improves.