Huseyin Sanverdi, the mayor of the nearby town of Reyhanli, Turkey, said a vehicle bearing Syrian plates and packed with explosives blew up at the Cilvegozu gate in the southern province of Hatay, Today's Zaman reported.
Sanverdi said four of the dead were Turkish, while the others were Syrian nationals.
The explosion took place in the "no-mans-land" between the Turkish and the Syrian gates.
Separately, in Syria rebel forces took control of the dam over the Euphrates dam at al-Tabaqa, the British newspaper The Guardian reported.
Mataz Suheil, a spokesman for the Syrian Observatory for Human Rights, said the rebels were largely from Jabhat al-Nusra, a jihadist group considered a terrorist organization by the United States.
The dam is considered strategically important for energy and agriculture.
The Syrian Network for Human Rights reported 76 deaths across Syria Sunday, including six children. The bulk of the deaths were in Deir al-Zor, Aleppo and the Damascus area.