The Islamic State claimed responsibility for bombings at three restaurants in northeastern Syria, which killed 18 people and injured about 45.
The attacks happened in a Christian neighbourhood of Qamishli, in the province of Hasakah, when the locals were preparing celebrations for the New Year.
At least two of the attacks were carried out by suicide bombers, according to the Kurdish YPG militia. The Britain-based Syrian Observatory for Human Rights said that the bombs detonated near a security checkpoint. The bombings severely damaged the scene of the blasts.
"Three explosions, [at least] one by a suicide bomber inside a restaurant, hit... Qamishli city in Hasakeh province," the Rami Abdel Rahman of the Observatory told AFP.
The New Year celebrations were cancelled after the bombings, and the Assyrian-Syriac Churches released a statement saying, "We dedicate this evening to prayers for the victims of those attacks. We pray for our region and country amid the bloody war that claims lives of civilians every day."
"Dozens of dead and wounded in the bombings by the fighters of the Islamic State in different parts of Qamishli city," Amaq reported.
In the past, the IS militants tried to capture the Hasakeh province where the city of Qamishli is located, but were pushed back by Syrian and Kurdish forces.
Syrian Prime Minister Wael al-Halqi condemned the attacks on the restaurants owned by Christians.
"These terrorist explosions will make us more determined and firm for confrontation to liberate every part of Syrian land," he said on Syria's state news agency SANA.
In other parts of Syria, air strikes lasting two days on IS-dominated areas killed 15 people. About 55,219 people were killed in the civil war in the year 2015 alone, among whom some 20,000 were civilians, including 2,574 children, according to statistics released by the Syrian Observatory.
US-based Assyrian Universal Alliance released a statement calling for the attacks against Christians in Syria and Iraq be termed as genocide.
"These cowardly attacks are directed at uprooting Assyrians from their ancestral lands. The utter failure of the non-Christian forces in control of the area to avert such inhumane attacks on innocent people is not only unacceptable but unpardonable," said Yonathan BetKolia of AUA.
In a separate statement on a local news channel, Father Touni Hannah, condemned the attacks that cause loss of lives.
"People were making their preparations to celebrate this Eve, but they were shocked with the brutal attacks that killed and wounded dozens of civilians," Hannah said.
"We hope the year 2016 would bring peace to Syria and the region after years of bloodshed."