Turkish authorities have detained at least 15 academics after they called on the government to stop "breaches of rights" during the army's military offensive against Kurdish rebels in the country's southeast.
Friday's detentions over the petition, which was signed by more than 1,000 academics, targeted those working for a state university in the northwestern city of Kocaeli.
The probe launched into the academics on Thursday looks into possible charges of insulting the state and engaging in "terrorist propaganda" on behalf of the Kurdistan Workers' Party (PKK), which is engaged in a bloody battle with Turkish forces. State media reported that further detentions were to follow.
"We ask the state to put an end to the violence it has been inflicting on citizens right now," the petition released earlier this week said.
"We, as academics and researchers of this country, declare that we will not be silenced [and] become a party to this crime," it added.
Q&A: Turkey's 'fight against terrorism legitimate'
The petition, which was also signed by renowned foreign academics such as Noam Chomsky and David Harvey, also called on the government "to stop declaring military curfews in the region and punish violators of human rights" within the security forces.
It also called for payment of compensation to citizens who suffered during the operations and for the preparation of conditions for peace talks to commence.
Ertan Aydin, an MP with the governing Justice and Development Party, told Al Jazeera that the declaration was unfair, merely criticising the state and sympathising with the armed group.
"The language of this text has nothing to do with peace. It openly supports a group recognised as a terrorist organisation by the world," he said.
"The petition falls short of criticising the PKK and only bashes the state as if the group does not carry out all the horrible atrocities going on in the region."
The declaration does not mention the outlawed PKK in any part of the text.
Turkey and PKK announced a ceasefire in 2013 but it collapsed last July. Fighting has since resumed, with Turkey running an air campaign against the group that launched an armed rebellion more than 30 years ago.
The operations have been criticised by rights groups for alleged disproportionate use of force and civilian deaths, a claim denied by Turkish officials, who blame the PKK for civilian deaths.
Cengiz Aktar, one of the signatories of the declaration, told Al Jazeera that Turkey's southeastern region was going towards secession because of the wrong policies followed by the government, adding that the petition called for an end to this.
"The state has always been trying to resolve the Kurdish issue through force since the establishment of the republic, apart from the recent short ceasefire," the Turkish associate professor of political science said.
"We are at a point of spiralling violence. One side's violence against the other has been creating further counter-violence ... The region is in the process of becoming the next Kosovo, which broke away from Serbia, after a long time of violence. The sides should start negotiations right away in order to avoid this."
President Recep Tayyip Erdogan and Prime Minister Ahmet Davutoglu have sharply criticised the petition, and Erdogan even called on the judiciary to act against the "treachery" of the signatories.
Aktar, the academic, told Al Jazeera that regulations in Turkey on "insulting Turkishness" and "terror propaganda" are vaguely defined.
"These can be used against any sort of remarks to start an investigation. Anything easily can be included or excluded from their coverage," he said.
READ MORE: Deadly car bomb targets police post in southeast Turkey
In the latest violence in the conflict, a car bomb blast near a police building in the Kurdish-majority province Diyarbakir in southeastern Turkey killed six people, including children, and injured at least 39 others on Thursday.
The ruling party MP Aydin said that "the state, of course, can be criticised, but the text is totally unfair.
"The PKK kills civilians. The attack in Diyarbakir yesterday, which killed children, is the most recent proof of that," he added.
The group has been fighting against the Turkish state since 1984, initially for Kurdish independence, although it now presses for greater autonomy and rights for the Kurds.
Follow Umut Uras on Twitter: @Um_uras
Source: Al Jazeera