UN inspectors are investigating at least three alleged chemical weapons attacks in Syria that happened after August 21.
Little is known about the latest three alleged attacks, which the Syrian government asked the UN to investigate.
The August 21 attack left hundreds dead; the resulting outcry led Syria to offer up its chemical weapons arsenal.
Inspectors are due in Syria next week – the UN will vote on the visit later.
UN inspectors are investigating at least three alleged chemical weapons attacks in Syria that happened after August 21
In Syria itself the violence goes on. Activists said a car bomb killed at least 20 people near a mosque in Rankus, a town north of Damascus, just after Friday prayers.
In a statement, the UN said its current inspection team in Syria is investigating seven allegations of chemical weapons use this year.
The team, led by Ake Sellstrom, arrived in Syria for its second visit on September 25 and hopes to finish its work by Monday 30 September, the statement said.
It is working on a “comprehensive report” into the allegations that it hopes to have finished by late October.
The UN listed the alleged attacks, which all took place this year, as Khan al-Assal on March 19; Sheikh Maqsoud on April 13; Saraqeb on April 29; Ghouta on August 21; Bahhariya on August 22; Jobar on August 24 and Ashrafieh Sahnaya on August 25.
Syria has pushed for the investigation of the three post-21 August incidents.
UN chemical weapons inspectors are expected to return to Syria on Wednesday, according to Russian government.
Deputy Foreign Minister Sergei Ryabkov said they would investigate alleged chemical weapons attacks at Khan al-Assal, Sheikh Maqsoud and Saraqeb, according to the Interfax news agency.
UN chemical weapons inspectors are expected to return to Syria
They had been preparing to do so when chemical weapons were fired at suburbs of Damascus on August 21.
Last week, the UN inspectors confirmed the nerve agent sarin was used in that attack.
They were not asked to ascertain who fired the sarin-filled artillery rockets that hit eastern and western parts of the Ghouta agricultural belt, killing hundreds of people, but Western powers have claimed it could only have been carried out by Syrian government forces.
The Syrian and Russian governments have challenged them to present firm evidence, and instead claimed that rebels were responsible.
Secretary of State John Kerry says the US has evidence that the chemical nerve agent sarin was used in a deadly attack in Damascus last month.
John Kerry said samples from hair and blood gathered after the attack “tested positive for signatures of sarin”.
The US blames the Syrian government for the August 21 attack.
President Barack Obama has vowed punitive action but wants Congress to vote on it first.
Syria dismissed the delay and said it was ready for any strike.
UN experts have been in Syria gathering evidence to determine whether chemical weapons attacks have taken place on various occasions. They have now arrived in the Netherlands with samples for analysis.
The biggest and deadliest apparent attack took place on August 21 in east Damascus. The US says more than 1,400 people were killed.
Washington said only the Damascus government has the capacity to launch such an attack.
Syria has denied it was responsible and blames the rebels.
John Kerry says the US has evidence that the chemical nerve agent sarin was used in a deadly attack in Damascus last month
John Kerry implied that the US evidence was supplied by its own sources, rather than via the UN inspectors.
“In the last 24 hours, we have learned through samples that were provided to the United States that have now been tested from first responders in east Damascus and hair samples and blood samples have tested positive for signatures of Sarin,” Kerry said on NBC’s Meet The Press.
“So this case is building and this case will build.”
The US has previously said it had similar evidence of sarin use in other attacks.
John Kerry also said he was confident that Congress would give its approval for the US to launch strikes against Syria after it reconvenes on September 9.
Congressmen “will do what is right because they understand the stakes”, he said, declining to explain whether Barack Obama would press ahead even if Congress voted against.
Syrian Deputy Foreign Minister Faisal Mekdad said Barack Obama’s decision to delay the strikes pending a vote in Congress was just “a political and media manoeuvre”.
Syrian President Bashar al-Assad remained defiant on Sunday, saying: “Syria… is capable of facing up to any external aggression just as it faces up to internal aggression every day, in the form of terrorist groups and those that support them.”
The Syrian government has been fighting rebel forces since March 2011.
More than 100,000 people are estimated to have died in the conflict, and at least 1.7 million have become refugees.
Syria is known to have extensive supplies of chemical weapons.
Barack Obama has often said that using them would cross a “red line”, prompting US intervention.
On Saturday, Barack Obama said any action would be limited, ruling out a ground invasion.
Congress is due to reconvene on September 9, meaning any military operation would not happen until then.
The opposition Syrian National Coalition (SNC) said President Barack Obama’s decision to delay any strikes in Syria was a “failure in leadership” and could “embolden” the forces of President Bashar al-Assad.
Arab League foreign ministers are meeting in Cairo on Sunday, with Saudi Arabia urging them to back calls for strikes against Syria.
The UK has ruled out taking part in any attack, after PM David Cameron failed to win the support of parliament last week.
That leaves France as the only other major power that has said it could strike against Syria – though it says it will not act on its own before the vote in the US Congress.
UN experts arrive in The Netherlands after finishing gathering evidence of alleged gas attack in Damascus suburbs.
They have left Syria having completed four days of site visits and evidence-gathering.
The experts arrived in the Netherlands on Saturday afternoon, after travelling from Damascus to Beirut earlier in the day.
The inspectors are seeking to determine what exactly happened in an alleged chemical weapons strike that killed hundreds in the Damascus suburbs on August 21.
The departure of the UN experts has heightened expectations of a possible international military strike against government forces.
UN officials say it may take weeks to analyze the samples gathered and to present conclusions, and UN spokesperson Martin Nesirky said that the inspectors would return to the country to investigate several other alleged chemical weapons attacks that have taken place during the country’s two-and-a-half year uprising against President Bashar al-Assad.
Saturday’s pullout comes as Washington suggested that the UN investigation would have no bearing on its decision about whether to attack Syria in retaliation for the alleged poison gas attack on civilians.
Russia, diplomats said, was hoping to use the time needed to complete the UN probe to slow down the push for air strikes.
UN experts arrive in The Netherlands after finishing gathering evidence of alleged gas attack in Damascus suburbs
“The samples that have been collected will be taken to be analyzed in designated laboratories, and the intention of course is to expedite the analysis of that sampling that’s been taken,” Martin Nesirky said.
He offered no timeline for when that analysis would be completed, but said all samples would need to be fully analyzed.
“This is not an electoral process, where you have exit polls and preliminary results,” he said.
“This is a scientific process. The only result that counts is the result of the analysis in laboratories and the analysis of the evidence that’s been collected through witness statements and so on.”
Martin Nesirky was addressing reporters while UN Secretary-General Ban Ki-moon was meeting with delegates from the five permanent UN Security Council members – Britain, China, France, Russia and the US – to update them on the UN investigation in Syria.
Two diplomats told the Reuters news agency that Ban Ki-moon informed the five delegations that analysis of the samples could take up to two weeks.
Ban Ki-moon cut short a visit to Europe amid concerns that Western powers are preparing military strikes against Syria to punish the government of Bashar al-Assad for the alleged chemical attack.
Angela Kane, the UN disarmament envoy who had visited Syria with the UN experts, left Damascus on Friday and was expected to brief Ban Ki-moon in New York later on Saturday.
France said on Friday it still backed military action to punish Bashar al-Assad’s government, and Washington pushed ahead with plans for a response despite a British parliamentary vote against a military strike.
An unclassified report by US intelligence agencies released on Friday said the attack killed 1,429 Syrian civilians, including 426 children.