No one claimed responsibility for Saturday's blast on the eastern entrance of the town of Salamiyeh which came hours after a cease-fire brokered by Russia and the US went into effect.
The Islamic State group has claimed responsibility for several bombings in Syria in recent weeks. Opposition activists in different parts of Syria said the situation has been "cautiously calm" since the truce went into effect yesterday.
The truce does not include either IS or al-Qaida's branch in Syria, known as the Nusra Front. The Syrian government and 97 rebel and militant groups said they will abide by the cease-fire.