Turkey's interior minister has said the death toll in the collapse of an eight-story apartment building in Istanbul has risen to 16.

Suleyman Soylu said early on Saturday that another body had been found in the rubble.

The building in Istanbul's mostly-residential Kartal district collapsed on Wednesday. The cause is under investigation but officials have said its top three floors were illegally built.

Soylu was speaking to reporters at the site as emergency services continued their work.

Thirteen out of 14 people who were rescued alive remain hospitalized with seven of them in serious condition.