Turkey's top court on Friday blocked implementation of a Government decree ordering police to inform their superiors before launching investigations issued by public prosecutors, local media reported.
The Government decree was introduced last week after police conducted raids targeting senior figures, including the sons of ministers and businessmen as part of a fast-moving corruption enquiry.
The decree was seen as a bid by Prime Minister Recep Tayyip Erdogan to contain the probe that poses the biggest threat to his 11-year rule.
Erdogan has swiftly responded to the investigation by sacking dozens of police chiefs and introducing measures seen by critics as an attempt to curb independent investigations by public prosecutors.
The Council of State, Turkey's top administrative court, said it was ruling against the decree which would cause "irrevocable damage", the Hurriyet newspaper reported.
Meanwhile, three lawmakers including a former minister resigned from Turkey's ruling Justice and Development Party (AKP) amidst a high-level bribery and corruption probe ensnaring close government allies.