SURUC - Turkey on Tuesday stepped up security on the border with Syria after a suicide bombing blamed on Islamic State extremists killed 31 people and raised fears of a spillover of the Syrian conflict onto its territory.

Monday's attack in a town on the border with Syria was one of the deadliest attacks in Turkey in recent years and the first time the government has directly accused the IS group of carrying out an act of terror on Turkish soil. Graphic images of the attack in Suruc shocked the country, with the press publishing front page photos of the mutilated corpses of pro-Kurdish activists lying on the ground covered in pages from broadsheet newspapers.

‘Security on our borders will continue to be increased,’ Prime Minister Ahmet Davutoglu said late Monday, adding that preliminary information pointed to an attack by IS jihadists. ‘This attack targets us all,’ he said, urging all political parties to demonstrate unity and vowing to bring the perpetrators to justice.

The blast ripped through a cultural centre in Suruc hosting about 300 socialist youth activists and most of the 31 dead and about 100 wounded were university students. The activists had arrived in the mainly Kurdish town to take part in a rebuilding mission for the flashpoint Syrian town of Kobane just over the border, which Kurdish forces had retaken from IS earlier this year.

Hundreds of pro-Kurdish activists took to the streets of Turkish cities on Monday night to protest against the attacks and government policy on Syria, with police in Istanbul using water cannon to disperse the rally. Dozens of people were killed in October in nationwide protests across Turkey against the government's perceived lack of support for Kurds battling IS jihadists.

The IS group, which has claimed swathes of territory in Syria and Iraq right up to the Turkish border has so far not claimed the attack. Turkey has long been accused by its Western partners of not doing enough to halt the rise of IS and even colluding with the group, allegations it vehemently denies. But Ankara has in the last weeks appeared to take a harder line against the group, rounding up dozens of suspected members in Istanbul and other cities.

‘Turkey has always taken measures against Daesh and similar kind of organisations,’ said Davutoglu, using a pejorative Arabic acronym for IS. ‘Daesh threatens not only Syrian people but also Turkey,’ he added. NATO member Turkey's main aim in the Syria conflict has been the ousting of President Bashar al-Assad and containment of pro-Kurdish groups and, so far, is yet to play a full role in the coalition against IS.

Nihat Ali Ozcan, security expert at Ankara-based TEPAV think tank, told AFP that the 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 faultlines in Turkey,’ he told AFP. Deputy Prime Minister Nurman Kurtulmus confirmed that the toll stood at 31, with 32 people were still being treated for their injuries, mostly in hospitals in the regional centre of Sanliurfa.

In televised comments, Kurtulmus said five corpses of the victims had already been handed over the their families. ‘We must show a common stand against terror,’ Kurtulmus said. Kurtulmus said there were ‘big suspicions’ over the identity of the bomber but said full information would only be given once the identity was certain. Davutoglu would travel to Sanliurfa later Tuesday, a government source told AFP, but it was not clear if he would head to the scene of the attack itself in Suruc. President Recep Tayyip Erdogan condemned the attack, saying Monday: ‘I curse and condemn the perpetrators of this brutality.’ The activists from the Federation of Socialist Youth Associations (SGDF), several of whom were in their teens, had travelled to Suruc from all over Turkey, according to Alp Altinors from the pro-Kurdish HDP party. Just before the attack, they had been pictured seated at tables enjoying breakfast and tea. White House spokesman Josh Earnest condemned the ‘heinous’ attack, as did Russian President Vladimir Putin, who labelled it a ‘barbaric act’ and called for greater international cooperation in fighting terrorism.