Turkish authorities have detained at least 14 academics accused of supporting "terror propaganda" after they signed a petition calling for an end to the government's crackdown on Kurdish rebels.
The arrests drew international condemnation and expressions of concern about freedom of expression in the country.
The state-run Anadolu news agency said the academics from Kocaeli University, near Istanbul, were detained during raids at their homes early Friday, adding that others were set to be taken in.
The detainees were among more than 1,200 academics who signed a statement condemning Turkey's "deliberate massacres and deportation" of Kurdish people in the southeastern part of the country.
The petition also called for an immediate end to the use of curfews and the resumption of the peace process with the PKK Kurdish rebel group.
Among the petition's notable foreign signatories were Noam Chomsky, the renowned U.S. leftist political analyst and linguist, and Slavoj Žižek, the prominent Slovenian philosopher and Marxist intellectual.
The academics were detained under laws about threatening the integrity of the state and terrorist propaganda, which can carry long prison terms. Prosecutors opened investigations into more than 130 academics who signed the petition in Istanbul.
Similar investigations are being carried out across the country. Also, the state body that administers universities announced that it was launching disciplinary probes.
The detentions were condemned by opposition parties, with one describing them as a dark stain on Turkish democracy.
Emma Sinclair-Webb, senior Turkey researcher of U.S.-based Human Rights Watch, called the detentions alarming.
"It marks a new threshold, really," she said. "It shows that there is an intolerance of even the most mild calls for political negotiations with the PKK, rather than military solutions to the Kurdish issue. We haven’t for many years in this country seen academics targeted in such a way. It's an extremely chilling and intimidating move."
But Turkish Foreign Minister Mevlut Cavusoglu strongly defended the crackdown. No country would consider “supporting or collaborating with a terror organization” as freedom of expression, he said.
The arrests came a day after Turkish President Recep Tayyip Erdogan said those who had signed the petition were traitors and supported terrorism.
Erdogan has described the academics as "so-called intellectuals" and "the darkest of people;" but the U.S. ambassador to Turkey, John Bass, strongly condemned the crackdown in a written statement, saying it was “having a chilling effect on legitimate political discourse across Turkish society.”
Observers said that was likely to be the object of the prosecutions — as a message to those critical of the current crackdown on the PKK to remain silent.
Turkish forces launched a new offensive in July against the PKK in southeastern Turkey, a move that ended a cease-fire of more than two years between the militants and the government. Erdogan further pledged in November to continue until every one of the militants was defeated.
Turkey, the United States and European Union all consider the PKK to be a terror group. The conflict between Turkey and the PKK has left 40,000 people dead since 1984.
VOA's Dorian Jones contributed to this report from Istanbul.