According to CNN, there has been an explosion near a hospital in Istanbul.
ISTANBUL (Reuters) - A large explosion has been heard in a mainly residential district of Turkey's largest city Istanbul, where a NATO summit is set for next week, state-run Anatolian news agency has reported.
Earlier on Thursday a small parcel bomb exploded outside the Hilton Hotel in the capital Ankara, where U.S. President George W. Bush is due to stay on Saturday night before attending the summit.