The state-run Syrian Arab News Agency said the bomb was planted by an armed terrorist group, Day Press News reported.
The government refers to armed opposition activists as terrorists.
Violence was reported in Deir Ezzor where a merchant was stabbed to death by an armed group. A man was also arrested for allegedly planting a car bomb, SANA reported.
U.N. observers toured Deir Ezzor and Harasta Monday while Herve Ladsous, the head of U.N. peacekeeping, met with Syrian government and opposition group representatives in the city of Homs.
A U.N. representative said both sides expressed their commitment to the peace plan brokered by former U.N. Secretary-General Kofi Annan.
Ladsous said the focus now needs to be on building dialogue and confidence between the two sides.
More than 9,000 people, mostly civilians have died in the protest movement against the Syrian government and tens of thousands of people have been displaced.
There is concern about recent clashes in neighboring Lebanon between Syrian government sympathizers and opponents, U.N. officials said. A representative for U.N. Secretary-General Ban Ki-moon said Ban is calling on all parties to make every effort to restore calm.
"The secretary-general stresses the need for Lebanon's continuing stability," the representative said. "He encourages all Lebanese parties to strengthen their efforts to date to overcome any emerging challenges on the ground."