The United Nations is checking with Russia over the reported information on the chemical weapons in Syria, UN spokesman Martin Nesirky said here Wednesday, adding that the work of UN inspectors "has been prepared to withstand independent scientific scrutiny."

Nesirky made the statement at a daily news briefing here when asked about the information Russia said it has received about the Aug. 21 attack in Ghouta, Syria.

The UN fact-finding group has put out a report which confirmed the chemical weapons attack on Aug. 21 on the outskirts of the Syrian capital of Damascus.

"The United Nations is checking with the Russian Permanent Mission to find out precisely what Deputy Foreign Minister (Sergei) Ryabkov said in Damascus," Nesirky said.

Ryabkov was reported to have said Wednesday that the UN inspection team did not pay enough attention to evidence provided by the Syrian government.

"On the face of it, these reported remarks are an attempt to call into question the secretary-general's investigation team led by Professor Ake Sellstrom and the credibility of its thoroughly objective report," the spokesman said.

UN chief Ban Ki-moon created the inspection team in March at the request of the Syrian government to find out whether chemical weapons were used in the Syrian conflict, but not who used them.

Meanwhile, the spokesman emphasized that Ban has said repeatedly, including on Tuesday to all 193 member states in the UN General Assembly, that the investigators are going to return to Syria as soon as practical to complete their work on Khan al Assal and all other pending credible allegations before completing the team's report.

An overall report would be completed at the end of that work, Nesirky added, including on the Aug. 21 incident, in which hundreds of people were reportedly killed.

The Syrian government and opposition are accusing each other of using chemical weapons in the conflict.

"The secretary-general has the fullest confidence in the professionalism of his team and their work and findings," the spokesman said. "They worked impartially and to the highest scientific standards despite the exceptionally difficult conditions of the war in Syria. They will continue to do so."

"The work of the Mission has been prepared to withstand independent scientific scrutiny," Nesirky said. "It adhered to the most stringent protocols available for such an investigation."

"The chain of custody for all samples has been meticulously documented and retained," he said. "The analytical results and factual findings in the report are based solely on the information obtained on the ground by the Mission."

The information has come from multiple sources of evidence, including samples from remnants of munitions, environmental and biomedical samples, information provided by survivors, patients, health workers and first responders, he noted.

The UN inspectors confirmed "unequivocally and objectively" that chemical weapons have been used in Syria, Nesirky said, adding that it detailed the types and trajectories of the rockets used to deliver their lethal pay-load that led to the deaths of so many civilians.

"The environmental and biomedical samples demonstrated the widespread nature of the attack," he said. "The terrible facts speak for themselves."