Turkish security forces briefly detained 27 academics accused of terrorist propaganda, local media said, over a declaration that criticized military action in the largely Kurdish southeast and urged an end to curfews.
President Tayyip Erdogan denounced the more than 1,000 signatories of the document, who included US philosopher Noam Chomsky, as "dark, nefarious and brutal" in a speech after Friday prayers.
In a more ironic tone, he said those who did not want to do politics in parliament "should go dig trenches or go to the mountains" - a reference to the tactics and hideouts of the Kurdish militant group PKK.
The Turkish opposition and the US ambassador to Turkey criticized prosecutors' actions in ordering investigations and home searches of academics across the country after Erdogan criticized the signatories in a speech on Thursday.
The declaration was inspired by clashes between government forces and the PKK since a ceasefire broke down in July. The military has locked down entire districts and pounded PKK outposts in residential areas, but denies accusations that its actions have endangered and killed civilians.