A suspected Islamic State suicide bomber killed at least 30 people, mostly young students, in an attack on a Turkish town near the Syrian border on July 20. Bodies lay beneath trees after the blast outside a cultural centre in the mostly Kurdish town of Suruc in southeastern Turkey, some 10 km (6 miles) from the Syrian town of Kobani, where Kurdish fighters have been battling Islamic State. The explosion tore through a group of mostly university-aged students from an activist group as they gathered to make a statement to the local press about a trip they were planning to help rebuild Kobani. Turkey's NATO allies have been seeking tighter controls on a porous border with Syria that runs alongside Islamic State-held territories. But monitoring is difficult with 1.8 million Syrian refugees now on the Turkish side and smuggling rife.

Rebuilding Kobani

Kobani was the site of one of the biggest battles against Islamic State last year and was secured by Syrian Kurdish fighters last month after repeated assaults.

The YPG drove the Islamist militants back from the town with the help of U.S. air strikes after months of fighting and siege.

The students from the Federation of Socialist Youth Associations had been planning a trip to Kobani to build a library, plant a forest and build a playground, Fatma Edemen, a member of the group wounded in the blast, told Reuters.

"I was behind a banner so I couldn't see the attacker, but we understand it was a suicide attack. I was thrown to the ground...I jumped up and began running before I even realised I was hurt," Edemen, a 22-year-old journalism student at Ankara University, said by telephone.

The blast came after a series of attacks on the Kurdish HDP party in the run-up to a June 7 election in Turkey, including two small bombs at a political rally in the city of Diyarbakir, which the party blamed on Islamic State sympathisers.

"What gives us pause about this attack is that while the others were haphazard and sloppy ... the size of this explosion suggests something more sophisticated," said Aaron Stein, an Atlantic Council fellow who specialises on Turkey and Syria.

"That would suggest organisation beyond a lone wolf cooking up something in their kitchen."