UPDATED 3:52PM: The suicide bomb attack near a soccer stadium in Istanbul has killed 29 people, 27 of them police personnel, and wounded 166, Turkish President Recep Tayyip Erdogan said.
Witnesses said police were deployed and had cordoned off the area as smoke rose from the newly built Besiktas Stadium.
They said gunfire could be heard in what appeared to have been an armed attack on police.
Ten people have been arrested in connection with the attacks.
The private NTV channel said the target of the attack was a bus for riot police.
Images broadcast on television showed more than a dozen ambulances on a street hugging the stadium and a police helicopter flying overhead with its search lights on.
CNN's Muhammad Lila said the blasts "were not minor blasts by any stretch."
A statement from Turkish President Recep Erdogan said they understood the attack aimed to maximise casualties.
More to come.