Turkey said Tuesday it had identified a suspect over a devastating suicide bombing on the border with Syria blamed on Islamic State jihadists, as the government rushed to bolster security on the porous frontier.
Thirty-two people were killed and more than 100 wounded on Monday when a bomb ripped through a gathering of young socialist activists preparing to take aid over the border into the flashpoint Syrian town of Kobane.
The attack in Suruc, in a mainly Kurdish region of Turkey, was one of the deadliest in the country in recent years and the first time the government has directly accused Islamic State of carrying out an act of terror on Turkish soil.
Police in Istanbul used tear gas and water cannon on Tuesday evening to disperse hundreds of pro-Kurdish activists who took to the streets to demonstrate over the attack and condemn government policy on Syria.
The crowd of around 800 protesters chanted anti-government slogans, including: "Murderer state will be brought to account."
Demonstrations also took place in the predominantly Kurdish town of Nusaybin on the border with Syria.
In harrowing scenes earlier in the day, relatives of the dead clutched the victims' coffins in a farewell ceremony in the southeastern city of Gaziantep ahead of their burial in towns across Turkey.
"One suspect has been identified. All the (suspect's) links internationally and domestically are being investigated," Prime Minister Ahmet Davutoglu said in the regional centre of Sanliurfa after visiting the wounded in hospital.
He added there was a "high probability" the attack was caused by a suicide bomber with connections to IS.
"We expect this investigation to be concluded as soon as possible," he said.
Davutoglu said the death toll had risen to 32 and that 29 injured victims were still in hospital.
"What is necessary will be done against whomever is responsible for (the attack)," Davutoglu said.
"This is an attack that targeted Turkey."
- 'Reinforce border security' -
The Hurriyet daily said Turkey's intelligence agency had previously warned the government that seven IS members -- three of them women -- had crossed into the country in recent weeks with the aim of carrying out attacks.
Previous reports had suggested the bomber was a woman but the DIHA news agency said the suspect was a 20-year-old Turkish man who had become involved with IS two months ago.
Davutoglu declined to give any further details on the suspect's identity.
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The IS group, which has captured swathes of territory in Syria and Iraq adjoining the Turkish border, has so far not claimed the Suruc bombing.
But Davutoglu said Turkey was taking steps to improve border security, which has long been criticised by Turkey's Western partners as lax.
He said the cabinet would discuss Wednesday an "action plan" on border security and the government would then take the "necessary measures".
"Conflicts abroad should not be allowed to spread to Turkey," he said.
Turkey has long been accused of not doing enough to halt the rise of IS and even colluding with the group, allegations it vehemently denies.
So far, Ankara has played only a secondary role in the US-led coalition against IS and been wary of backing the jihadists' Kurdish opponents, saying the priority is the ousting of Syrian President Bashar al-Assad.
But Davutoglu insisted the government had "never had any direct or indirect connection with any terrorist organisation".
In recent last weeks Ankara has appeared to take a harder line against the IS group, rounding up dozens of suspected members in Istanbul and other cities.
- 'Spillover into Turkey' -
Nihat Ali Ozcan, security expert at Ankara-based TEPAV think-tank, said the Suruc attack showed the confrontation between IS and Kurdish groups within Syria was "spilling over to Turkish soil".
"The attack could trigger ideological, ethnic and political fault lines in Turkey," he told AFP.
The activists from the Federation of Socialist Youth Associations (SGDF) had arrived in Suruc to take part in a rebuilding mission in Kobane, which Kurdish forces had retaken from IS earlier this year.
Pictures posted on social media showed the toys they had planned to give to the children of Kobane.
Just before the attack, they had been photographed seated at tables having breakfast. The identities of 30 of the 32 victims have been confirmed by the authorities.
The leader of the pro-Kurdish Peoples' Democratic Party (HDP) Selahattin Demirtas called on people to attend an international rally against "IS barbarism" in Istanbul at the weekend.
The governor of the region of Sanliurfa, where Suruc is located, announced that public rallies had been banned as a security precaution although the ruling was later reversed.
Dozens of people were killed in October in nationwide protests across Turkey against the government's perceived lack of support for Kurds battling IS.