Monitors’ vehicles damaged in incident in Khan Sheikhoun, with activists blaming security forces for 21 civilian deaths.
A car bomb has exploded in the eastern Syrian city of Deir az-Zor, killing nine people and wounding 100 others, according to state-run media.
The blast reportedly struck a parking lot for a military intelligence complex on Saturday.
State TV showed footage of damaged buildings, smoldering cars, and trucks turned upside down by the blast.
“A car bomb has exploded in the Ghazi Ayyash neighbourhood of Deir az-Zor”, Ikhbariya TV said, describing the blast as “a terrorist attack”.
The Syrian Observatory for Human Rights, a UK-based opposition group, also confirmed the explosion, saying it was followed by heavy gunfire.
It was the latest of a wave of deadly blasts that apparently targeted security agencies across the country in the past months.
The most recent bombing occured near an intelligence building in Damascus on May 10, killing about 55 people.
The unrest comes as the government of President Bashar al-Assad tries to quell a 14-month nationwide uprising.
Al Jazeera’s Hashem Ahelbarra, reporting from the Turkish city of Antakya, along the border with Syria, said that opposition groups accuse the government of staging the blasts as a ploy to make the country’s protest movement appear violent.
“A human rights activist group and activists on the ground have been brushing aside accusations of the government, saying these are similar tactics that had been used before by the government in different parts of the country to discredit the pro-democracy movement as radical and terrorist,” he said.
The Syrian National Council (SNC), the country’s main political opposition group, also blamed the government for the blast.
“The Syrian National Council places on the Syrian regime the entire responsibility for the criminal bombings in several Syrian cities, including the one today in Deir az-Zor,” a statement said.
“These repetitive blasts are part of the regime’s plan to sow chaos and trouble, given that it failed to repress the revolution of the Syrian people.”
Saturday’s bombing came as government troops clashed with members of the Free Syrian Army (FSA), an armed opposition group composed mainly of defected soldiers, across the country.
At least 10 FSA members were reportedly killed in clashes with government troops in the northern city of Idlib. The fighting in the district of Bab al-Hawa broke out soon after scores of soldiers defected.
Al Jazeera is unable to independently verify reports of violence, as the Syrian government has placed strict restrictions on reporting.