Turkey's environment minister has become the country's third Cabinet minister to announce his resignation on Wednesday as a result of a high-level corruption probe.
Erdogan Bayraktar announced he is stepping down during an interview on NTV television. In the interview, he also urged Prime Minister Recep Tayyip Erdogan to resign.
Earlier Wednesday, Economy Minister Zafer Caglayan and Interior Minister Muammer Guler both stepped down.
Their sons are among 24 people arrested last week on graft charges in the corruption case, which involves state-run lender Halkbank.
Bayraktar's son was detained in the probe but has not been formally charged.
The case is one of the largest-ever judicial probes into government corruption in Turkey. The investigation has centered on the alleged laundering of money from Iran to circumvent international sanctions on Tehran.
There are also allegations of bribery in the awarding of state contracts for land development.
On Sunday, Prime Minister Erdogan warned his rivals he will go after them and - in his words - "break their hands" if they use the widening scandal to undermine his rule.
As he made his comments, throngs of angry protesters gathered in the city's Kadikoy Square to call for the resignation of Erdogan's Justice and Development Party government.
The prime minister has responded to the Halkbank probe with a purge in the police force. Dozens of senior police officers were either fired or reassigned for failing to inform their superiors about the probe.
Ambitious urban development projects led by Erdogan, a former Istanbul mayor, were one cause of massive anti-government protests in June sparked by a police crackdown on a peaceful sit-in against plans to demolish a park in Istanbul.
At least six people died and 8,000 were hurt in three weeks of nationwide demonstrations against Erdogan's government.