Protesters march behind a banner reading "We know the killer" during a in Istanbul, following the deadly attacks in Ankara on October 10.  AFP

AFP/Ankara

Turkish investigators on Tuesday sought to firm up suspicions Islamic State jihadists were behind a double suicide bombing in Ankara that killed 97, as President Recep Tayyip Erdogan was to break days of silence over the blasts.
Prime Minister Ahmet Davutoglu on Monday said IS was the prime suspect behind Turkey's deadlist ever attack which saw bombs packed with ball bearings ripping through a crowd of leftist and pro-Kurdish activists at an anti-government peace rally in the capital.
Three days after the bloodshed, Ergodan -- who has come under fire over alleged security lapses -- was to make his first public remarks on the attacks at a joint news conference with visiting Finnish President Sauli Niinisto.
And Davutoglu and his wife Sare visited the scene of the attack, laying memorial wreaths outside Ankara train station.
There have been growing indications that the authorities are focussing on possible parallels or even links to a July 20 suicide bombing at a peace rally in Suruc on the Syrian border that killed 34.
The government blamed IS for that attack, which also targeted a gathering of pro-Kurdish and leftist activists.
The Ankara attack "bears similarities to the bombings in Suruc," Deputy Prime Minister Numan Kurtulmus said.  
He said "several arrests" had been without giving further details.
"We are carefully examining both the usual and alternative suspects with the help of these arrests," Turkish media quoted him as saying late Monday.
The Hurriyet daily said DNA testing on part of the suspected bomber's corpse matched that of a known IS jihadist who had been to Syria and then returned.
Over the weekend and on Monday, police arrested dozens of people with suspected links to IS in cities stretching from the Mediterranean resort of Antalya to the southern city of Adana.
Turkey's NATO allies have long pointed the finger at Ankara for not taking a tougher line as IS militants seized swathes of northern Iraq and Syria.
But following months of Western pressure, Turkey is now a full member of the US-led coalition against IS and allowing American jets to use its Incirlik air base for raids.
 
 'No security in place'
The attack has raised political tensions to new highs as Turkey prepares for a November 1 snap election, with polarisation within the country now greater than ever.
The pro-Kurdish Peoples' Democratic Party (HDP), which lost several members in the blasts, accused Ankara of turning a "blind eye" to IS in Syria.
"It seems there was no preventative work, no security arrangements in place" to thwart the bombing of the Ankara rally, HDP leader Selahattin Demirtas told CNN-International.  
"That increases the responsibility of the government," he added.  
His party on Tuesday admitted it had incorrectly put the death toll as 128, blaming inaccurate information.  
According to the health ministry, 53 people were still in intensive care on Tuesday.
Hundreds of labour activists gathered in front of Istanbul's Sirkeci train station -- the fabled terminus of the Orient Express -- in the hope of marching through the city to remember the dead.
"We know the killer!" read the slogan on several banners, accusing the government of complicity in the bombing. The government had ridiculed such claims.
 
Growing anger

But tensions rose after the police blocked their way, saying the rally was not appropriate following a ban issued overnight by the Istanbul authorities.  
Scuffles broke out as demonstrators clashed with truncheon-wielding police in riot gear, AFP photographers said.
Bereaved relatives had on Monday held the first funerals for the victims of the Ankara blast, shouting slogans against Erdogan and the government.
An protest in Istanbul's Gazi district -- a known stronghold of hard-left anti-government activists -- had descended into violence overnight as masked protesters threw Molotov cocktails at the security forces.
Among those buried was the youngest victim of the bombings, 9-year-old Veysel Atilgan, who was given a moving send-off by his classmates in Ankara, press reports said.
With Turkey on a high alert after the violence, the authorities on Tuesday defused a suspect package in front of Ankara train station.
The attacks came as the government was waging a relentless "anti-terror" offensive against the outlawed Kurdistan Workers' Party (PKK), even after the group announced a ceasefire at the weekend.
In the latest air raids on PKK targets, the military said 12 "terrorists" were killed in air strikes on their hold-outs in the southeastern Hakkari region.