A blast rocked the Syrian side of the Turkish-Syrian border Tuesday, Turkey's semiofficial Anatolian news agency reported.
Video shot by activists showed torrents of black smoke emerging from blazing vehicles at the crossing as survivors tried to help victims.
The LCC said the attack wounded many people.
The explosion, which happened near a border gate, comes a day after Turkish planes shot down a Syrian helicopter crossing into Turkey. It came down on Syrian territory, Turkish Deputy Prime Minister Bulent Arinc said.
Syria's state news agency SANA said the helicopter was watching for "terrorists" crossing the border and erroneously strayed into Turkish airspace, but was on its way back across the border when shot down.