The blast ripped through the centre in Suruc – a town just across the border from Kobane, which was itself later hit by a suicide vehicle bombing – blowing out the windows and starting a fire, witnesses said.
There was no immediate claim of responsibility for the attack in Suruç, the deadliest near Turkey’s border with Syria in more than two years.
The explosion comes weeks after Turkey deployed additional troops and equipment along parts of its border with Syria, concerned about the risk of spillover as fighting between Kurdish forces, rebel groups, Syrian government troops and Islamic State militants intensifies.
Hundreds of others were injured in the blast in the garden of the Amara Cultural Center, where about 300 members of the Federation of Socialist Youth Organizations (Sosyalist Gençlik) were meeting.
Kobane has been a symbol of resistance against the jihadists since IS fighters were driven out in January.
Kobane came under attack of Islamic State (IS) jihadists in early 2015 and thousands of people have crossed Mursitpinar border crossing and arrived in Suruc town fleeing violence.
“Terror has no religion, no country, no race”, President Tayyip Erdogan said of the bloodiest such attack in Turkey since at least 50 people were killed in the town of Reyhanli near the border in 2013.
“We wanted to do something, but they would not let us”, she said.
The senior Turkish official said authorities had evidence that the attack was a suicide bombing.
A video posted on Facebook by one of the youth activists showed at least 20 people lying on the ground, and others trying to comfort the wounded.
Late Friday, the Islamic State carried out a massive auto bombing in a busy market in Iraq that killed 126 adults and children celebrating the end of the holy month of Ramadan. “Such despicable terrorist attacks on #Turkey’s integrity and peace will never reach their goal”, he said.
A Kurdish official in Kobane, Idriss Naasan, told The Associated Press that a second bomb went off in the Syrian town, causing minor damage and no casualties.
Almost 100 were injured in Suruc, which is home to a large number of Syrian refugees. Three Kurdish fighters were killed, he said.
A team of experts has been sent to Suruc, neighboring the Syrian town of Kobani, and security forces have taken measures around the area, the ministry said in a statement.