At least 27 people were killed and scores of others injured in a blast in Turkey's Sanliurfa province near the Iraqi border on Monday, a media report said.
"We are concerned that the number of deaths will increase," Hurriyet Daily quoted Turkey's interior ministry as saying in a statement following the blast which occurred in Suruc district in the morning.
The district houses many refugees who fled fighting in Kobane between Islamic State (IS) militants and Kurdish fighters since last September, when IS overran Suruc.
The ministry said it suspected the blast was carried out by an 18-year-old female suicide bomber from the IS terror group.
About 300 members of the Federation of Socialist Youth Associations were staying at the Amara Culture Centre, as part of a summer expedition to help rebuild Syrian town of Kobane, which lies across the border from Suruc district, the media report said.
The centre, run by the Suruc municipality under the control of the Peoples' Democratic Party (HDP), frequently hosts visiting journalists and volunteers who work with refugees from Kobane.
"It's a big massacre. The probability of a suicide bomber is very high," Leyla Guven, an HDP official, said.
