A referendum on controversial amendments to Turkey's Constitution has been scheduled for September 12, the electoral board said yesterday.

"The Higher Electoral Board has decided unanimously that... the vote will be held on September 12," the body's deputy head, Kirdar Ozsoylu, told reporters.

The decision was a setback for the Islamist-rooted government, which had sought to hold the referendum in July under a measure passed earlier this year.

But the electoral board ruled that, under Turkish law, legislation affecting voting procedures can be applied only a year after its introduction, Mr Ozsoylu said.

The amendment package, drawn up by the ruling Justice and Development Party (AKP) and approved by Parliament last week, is aimed at curbing the powers of the judicial elite and the military, which have often clashed with the government.

The opposition charges that the AKP designed the amendments to tighten its grip on power by extending government control over key judicial bodies, undermining the system of checks and balances.

The AKP has rejected the accusations, insisting the package would bring Turkey closer to the European Union's democracy norms.