A powerful Syrian rebel group has issued a rare statement condemning "in the strongest terms" two suicide attacks that hit the capital Damascus.

Ahrar al-Sham describes Wednesday's doubling bombing, including an attack at a central court complex that killed at least 32 people, as "criminal terrorist blasts".

There was no immediate claim of responsibility for the blasts - the second wave of deadly attacks in the capital in less than a week after a double bombings on Saturday that killed 74 people.

In a separate incident on Wednesday, 14 children were among 25 people killed in an air strike on the northern Syrian city of Idlib, according to a monitor.

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Following the violence, Antonio Guterres, the UN secretary-general, urged adherence to a ceasefire brokered by Russia and Turkey in December, and progress towards peace, which he called "a moral and political imperative both for the Syrian people and for the world".

Peace is something that ordinary Syrians, including many who supported the uprising, are desperate for as the conflict enters its seventh year.

"When we began to demonstrate, I never thought it would come to this. We thought it would end in two, three months, a year at most," Abdallah al-Hussein, a 32-year-old footballer from the town of Saraqeb in Idlib province, told AFP.

"Whether this war is ended with weapons or peacefully doesn't matter. People want to live in peace."

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More than 320,000 people have been killed in Syria since the conflict began in March 2011, with President Bashar al-Assad's government now holding the upper hand and rebel forces increasingly divided and dispirited.

In recent months, the opposition has suffered a series of reversals, including being forced from their one-time stronghold of east Aleppo in December.

And peace talks have made little progress towards resolving the conflict, with rebels declining to even attend the latest round of negotiations in Kazakhstan which wrapped up on Wednesday.

The conflict began in 2011 with peaceful demonstrations inspired by similar movements during the so-called Arab Spring, calling on Assad to implement reforms.

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A US defence official told AFP on Wednesday that up to 1,000 additional American troops could deploy to northern Syria under provisional Pentagon plans.

There are currently between 800 to 900 US personnel on the ground aiding the push for the ISIL bastion of Raqqa, and the official said the new scheme could allow for up to 1,000 more.

"That's one of the proposals that's on the table for discussion," the official said, speaking on condition of anonymity.

The war's brutality has prompted international outcry, with UN human rights chief Zeid Ra'ad al Hussein, this week describing Syria as "a place of savage horror and absolute injustice".

The Syrian Civil War Reaches Its 6th Year

Source: Al Jazeera and news agencies

Middle East, Syria's Civil War, War & Conflict