The bombs went off in the city center, near a security point run by government troops, said the Britain-based Syrian Observatory for Human Rights, which relies on a network of activists and other sources inside Syria. It said the death toll rose to 18 after two more people died of their wounds. SANA`s toll remained at 16.
A claim of responsibility by the Islamic State group later circulated on social media. The extremists have suffered some of their worst setbacks in battles with Kurdish fighters in Syria, and have carried out dozens of suicide attacks against the Kurds, including several in Qamishli.
The Kurdish fighters, aided by U.S.-led airstrikes, have captured significant territory from IS in northern Syria.
Syrian Prime Minister Wael al-Halqi strongly condemned the explosions, which targeted the Miami and Gabriel restaurants, saying that they reveal the "brutality of criminal gangs."
"These terrorist explosions will make us more determined and firm for confrontation to liberate every part of Syrian land," he said in remarks carried by SANA. Syrian President Bashar Assad`s government uses the term "terrorist" to refer to all of those fighting against his rule.
The news agency said the blasts also severely damaged the buildings.
Elsewhere in Syria, two days of airstrikes on IS-controlled areas around the ancient Roman city of Palmyra killed at least 15 people, including at least one woman, the Observatory said. Palmyra and its famed ruins, once a major tourist draw, fell to IS in May.
Fighting between pro-government forces and IS militants continued around Homs province, where Palmyra is located, with bombs striking a salt factory, a hospital wing, and other targets, the Observatory said.
SANA said government airstrikes hit extremist targets across the country and ground troops moved into several villages in the eastern countryside of Hama province.
The Observatory meanwhile released its tally of this year`s deaths in the civil war, saying a total of 55,219 people were killed in 2015.
Some 20,000 of those were civilians, including 2,574 children, while 7,728 were rebel combatants and some 16,000 were government troops and allied militiamen, it said.
Lebanon`s Shiite movement Hezbollah lost 378 fighters in Syria in 2015, it added.
Syria`s conflict began with largely peaceful protests in 2011 against the rule of President Bashar Assad, which quickly escalated into civil war following a harsh crackdown on dissent. The conflict has killed more than 250,000 people and generated a massive refugee crisis.
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