Turkey has formally charged 99 generals and admirals in connection with the weekend’s thwarted coup attempt, just under a third of the country’s 356 top military officers.
Authorities have banned all academics from travelling abroad, as the purge of state employees suspected of being connected to the failed coup continues.
More than 50,000 people have been rounded up, sacked or suspended.
President Recep Tayyip Erdogan is expected to announce further measures.
He chaired a five-hour emergency meeting of the National Security Council and was expected to lay out a series of emergency measures later on Wednesday, sources told the Reuters news agency.
So far about 1,577 university deans (faculty heads) have been asked to resign in addition to 21,000 teachers and 15,000 education ministry officials.
They are suspected of having links to the alleged mastermind of the coup, US-based cleric Fethullah Gulen – who denies any involvement.
Some 626 institutions have also been shut down, most of them private educational establishments, officials say.
Meanwhile, Turkish F-16 fighter jets launched an operation to check reports that two missing coastguard vessels were trying to reach Greek waters, but details were few.
As soon as it became clear that the coup had failed on Saturday, the purges began – first with the security forces, then spreading to Turkey’s entire civilian infrastructure.
Human rights group Amnesty International has warned the purges are being extended to censor media outlets and journalists, including those critical of government policy.
“We are witnessing a crackdown of exceptional proportions in Turkey at the moment.
“While it is understandable, and legitimate, that the government wishes to investigate and punish those responsible for this bloody coup attempt, they must abide by the rule of law and respect freedom of expression,” Amnesty’s Turkey researcher Andrew Gardner said.
Extending the clear-out to include the education sector, university rectors have been asked by the Higher Education Council to “urgently examine the situation of all academic and administrative personnel” linked to what it calls the Fethullah Terrorist Organisation (Feto) and report back by 5 August.
It has also told universities that academics who are already abroad on work or study missions should return home “within the shortest possible time”.
A government official told Reuters that the ban on academics travelling abroad was a temporary measure implemented to stop alleged coup plotters in universities from fleeing abroad.
Turkey is pressing the US to extradite Mr Gulen and the issue was raised during a phone call between US President Barack Obama and President Erdogan on Tuesday, the White House said.
Spokesman Josh Earnest said a decision on whether or not to extradite would be made under a treaty between the two countries.
Meanwhile, Turkey’s military announced that it had resumed cross-border strikes against Kurdish rebel targets in northern Iraq, killing about 20 alleged militants. They were the first since the attempted coup.
F-16 jets were reported to have targeted positions of the banned Kurdistan Workers Party (PKK) in Iraq’s Hakurk region, Anadolu Agency reported.
The Turkish military has regularly targeted suspected PKK bases in Iraq since last year.