Turkey's government said on Monday Islamic State was the prime suspect in suicide bombings that killed at least 97 people in Ankara, but opponents vented anger at President Tayyip Erdogan at funerals, universities and courthouses.
The father of three men wounded in the blasts told Reuters one of his sons had described seeing one of the bombers carrying a bag on his back and one in his hand, and called out "stop" before the bomb detonated.
Prime Minister Ahmet Davutoglu said Saturday's attack, the worst of its kind on Turkish soil, was intended to influence the outcome of November polls Erdogan hopes will restore a majority the ruling AK party lost in June. Officials say there is no question of postponing the vote.
Two bombs struck seconds apart, targeting a rally of pro-Kurdish activists and civic groups near Ankara's main train station.
"If you consider the way the attack happened and the general trend of it, we have identified Islamic State as the primary focus," Davutoglu told Turkey's NTV television. "It was definitely a suicide bombing...DNA tests are being conducted. It was determined how the suicide bombers got there. We're close to a name, which points to one group."
The Haberturk newspaper has cited police sources as saying the type of explosive and the choice of target pointed to a group within Islamic State known as the 'Adiyaman ones', a reverence to Adiyaman province in southeastern Turkey.
Turkey is vulnerable to infiltration by Islamic State, which holds swathes of Syrian land abutting Turkey where some two million refugees live. But there has been no word from the group - usually swift to publicly claim responsibility for any attack it conducts - over the Ankara bombing or two very similar incidents earlier this year.
Opponents of Erdogan, who has led the country over 13 years, blame him for the attack, accusing the state at best of intelligence failings and at worst of complicity by stirring up nationalist, anti-Kurdish sentiment.
The government, facing a growing Kurdish conflict at home and the spillover of war in Syria, vehemently denies such accusations.
But the sheer range of possible perpetrators - from Islamic State and Marxist radicals to militant nationalists and Kurdish armed factions - highlights deep fissures running through Turkish society. At stake is the stability of a NATO country seen by the West as a bulwark against Middle Eastern turmoil.
Hundreds chanting anti-government slogans marched on a mosque in an Istanbul suburb for the funeral of several of the victims, attended by Selahattin Demirtas, leader of the pro-Kurdish parliamentary opposition Peoples' Democratic Party (HDP), which says it was the target of the bombings.
Riot police with water cannon and armored vehicles stood by as the crowd, some chanting "Thief, Murderer Erdogan" and waving HDP flags, moved towards the mosque in the working class Umraniye neighborhood of Istanbul.
Several labor unions also called protests. Hundreds of people, many wearing doctors' uniforms and carrying Turkish Medical Association banners, gathered by the main train station in Ankara where the explosions happened to lay red carnations but were blocked by riot police, a Reuters witness said.
Lawyers at an Istanbul courthouse chanted "Murderer Erdogan will give account" as colleagues applauded, footage circulated on social media showed.
Erdogan, accused by opponents of an increasingly authoritarian and divisive style, has overseen a purge in the judiciary of elements he believes to have been colluding with a U.S. based cleric-rival planning a coup against him.