The European Union says Turkey's measures against the education system, the judiciary and the media following the failed coup are "unacceptable".
In a statement, High Representative Federica Mogherini and Commissioner Johannes Hahn said they were "concerned" by Turkey's decision to declare a state of emergency.
The move gives Turkey's leaders "far-reaching powers to govern by decree".
Thousands of people have been sacked or arrested following the failed coup.
The two senior EU officials urged President Recep Tayyip Erdogan to respect the rule of law, rights and freedoms.
And they also warned Turkey over its decision to suspend the European Convention on Human Rights, saying it must stick to the conditions by which a suspension is permitted.
Turkey is a candidate to join the EU, but its accession talks have progressed extremely slowly.
Earlier, German Foreign Minister Frank-Walter Steinmeier urged Turkey to maintain a sense of proportion in its response to the coup attempt.
The human rights organisation Amnesty International has described the authorities' actions as "a crackdown of exceptional proportions".
Analysis: Mark Lowen, BBC News, Istanbul
The state of emergency gives President Erdogan radically enhanced powers for three months.
He and the cabinet will be able to fast-track legislation through parliament, where the government holds a majority; the constitutional court will be unable to challenge it; there could be restrictions on publications and freedom of assembly; and broader powers of arrest.
The question is: how will this be applied?
The government insists it will not affect the daily life of citizens and that the state of emergency will only root out the "virus" behind the coup. It points out that similar measures were adopted in France after the Paris attacks last November. And President Erdogan says this actually aims to protect democracy and human rights.
But given the criticism of the president for curbing both while in office, doubts persist over how a leader seen by opponents as increasingly authoritarian will use this, especially given the recent purges.
France and Germany have spoken out loudest, but Mr Erdogan has been typically forthright in his response, telling the French foreign minister to "mind his own business".
In the immediate aftermath of Friday's failed coup, thousands of soldiers - including high-ranking generals - were arrested, along with members of the judiciary.
Since then more than 50,000 state employees have also been rounded up, sacked or suspended and 600 schools closed.
Academics have been banned from foreign travel and university heads have been forced to resign.
The government has also revoked the press credentials of 34 journalists, according to Turkish media.
The president has blamed the coup attempt on US-based cleric Fethullah Gulen, a former ally who is believed to have much support in Turkey's military and state institutions.
Mr Gulen has denied any involvement.
Turkey is seeking the cleric's extradition, but the US says it needs to see hard evidence of his involvement in the coup attempt.
Turkey's thwarted coup
- 22:00 (19:00 GMT) Coup attempt launched in Istanbul and Ankara on 15 July
- Bosphorus bridges blocked in Istanbul; warplanes attack police and intelligence buildings in Ankara
- Midnight: President Erdogan, who is on holiday in south-west Turkey, appears on CNN Turk via FaceTime to urge resistance
- Parliament in Ankara is bombed and soldiers and tanks fire at protesters
- 03:00 President Erdogan arrives safely at Istanbul airport and is mobbed by supporters
- 06:00 Soldiers surrender on the Bosphorus bridges
- At least 260 people were killed and 1,400 wounded
All timings approximate
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