TURKEY- The sons of two Turkish government ministers have been charged in connection with a huge corruption investigation, along with the head of the state-owned bank and at least a dozen other people.

The controversial arrests began on Tuesday when police launched a series of dawn raids in Istanbul and Ankara.

On Thursday the head of Istanbul's police was forced from his position, and more than 30 senior police officers have reportedly been sacked.

Baris Guler, the son of Interior Minister Muammer Guler and Kaan Caglayan, son of Economy Minister Zafer Caglayan was among those detained, as is the chief executive of the state-owned Halkbank, Suleyman Aslan.

Prime Minister Recep Tayyip Erdogan has denounced the investigation as a "dirty operation" against his government.

The son of a third minister - Environment and Urban Planning Minister Erdogan Bayraktar - was among those released after hours of questioning.