UNITED NATIONS - About 150 Syrian civil society groups are accusing UN Secretary-General Antonio Guterres of rewarding Russia by dispatching the special envoy to the Sochi peace congress.

In a letter to Guterres, the groups, including a number of opposition local councils, said envoy Staffan de Mistura attended the congress even as the Syrian regime continued to show little interest in UN-led peace talks. "Instead of an onus on Russia to get the regime to the table in a meaningful way before Russia was rewarded, you gave them the reward of UN legitimacy upfront," said the letter released Thursday.

Syria's main opposition coalition and Kurdish groups boycotted the congress held this week, just days after a ninth round of UN-led talks in Vienna failed to yield progress. The 1,400 delegates at the congress agreed to set up a committee to draft a post-war constitution.

The opposition fears that the new constitution will pave the way to allowing Syrian President Bashar al-Assad to stay in power despite six years of bloodshed.

UN spokesman Stephane Dujarric said that Russia had provided assurances that the result of the congress would be "a contribution" to the UN-led peace talks in Geneva. The West views Russia's peace efforts in Syria with suspicion, concerned that Moscow is seeking to sideline the UN talks.

A Syrian government source said Thursday that the congress was "the cornerstone of the political process and solid base upon which dialogue will be launched from now on."

US concerned sarin gas used

in Syria: Mattis

The United States is concerned that sarin gas may have been recently used in Syria, US Defense Secretary Jim Mattis said Friday, as Washington steps up the pressure on Bashar al-Assad's regime to put an end to chemical attacks.

Mattis told reporters that chlorine gas was known to have been weaponized "repeatedly" in attacks in Syria, but added: "We are even more concerned about the possibility of sarin use, and we are looking for the evidence." The Pentagon chief cited reports from NGOs and rebel groups in the battlefield who say the chemical weapon has been used, although he stressed that the United States currently has no evidence to support those claims. "But we are not refuting them - we are looking for evidence of it since clearly we are dealing with the Assad regime that has used denial and deceit to hide it," he said. "They would be ill-advised to go back to violating the chemical convention."

Mattis's remarks come a day after senior administration officials said Washington was not ruling out fresh military action against the Syrian regime in the wake of suspected sarin and chlorine attacks.

President Donald Trump "hasn't excluded anything" in the bid to halt the program, a senior US official told AFP. "Using military force is something that is still considered." There have been more than 260 reports of chemical attacks in Syria, some of which have been verified by UN-backed inspectors and attributed to the Assad regime. Aside from the threat to Syrian civilians, Washington is worried that the well-documented chemical attacks - systematically denied by Damascus and its Russian ally - is undermining long-standing taboos on their use.

The Assad regime appears to have altered course only slightly since the United States fired 59 Tomahawk cruise missiles at a Syrian airfield in 2017, after a large chemical attack on rebel-held Khan Sheikhun.

Instead of dropping barrel bombs filled with chemical agents from helicopters, senior administration officials say that mortars and other ground-based delivery systems are now being used.

The chemical of choice has most often been industrial chlorine, which is easy to produce and legal to possess, rather than sarin, which is banned by the Chemical Weapons Convention.


Regime attack on Syria's Ghouta kills seven

Bombardment by the Syrian regime killed at least seven civilians Friday in the rebel-held enclave of Eastern Ghouta, east of Damascus, a monitoring group reported.

The bloodshed came a day after the latest suspected chlorine attack by the regime of President Bashar al-Assad on Ghouta, which has been besieged by government forces since 2013.

Senior US administration officials on Thursday said President Donald Trump did not rule out military action, such as the cruise missiles fired at a Syrian airfield in April 2017.

On Friday, at least three civilians, including a child, were killed in air strikes on the town of Arbin, the Syrian Observatory for Human Rights said.

The Britain-based war monitor, which relies on a network of sources on the ground across Syria, said shelling killed another four civilians, including in Ghouta's main town of Douma.

The Observatory could not confirm local reports of a chlorine attack on the Eastern Ghouta region on Thursday but it reported at least two likely uses of chlorine in attacks in January.

US Defence Secretary Jim Mattis said Friday that chlorine gas was known to have been weaponised "repeatedly" in attacks in Syria lately.

"We are even more concerned about the possibility of sarin use, and we are looking for the evidence," he said.

Syria's war has killed more than 340,000 people and displaced millions since it began in March 2011 with the brutal repression of anti-government protests.