US data on Syria attack 'not objective'

The Kremlin has called a deadly poison gas attack in Syria's Idlib province earlier this week a "monstrous crime", but said Washington's conclusions about the incident were not based on objective data.

"This was a dangerous and monstrous crime, but it would be incorrect to hang labels (to identify those who did it)," Kremlin spokesman Dmitry Peskov told reporters on a conference call.

The use of chemical weapons was "unacceptable", he said, urging the Syrian army to ensure such arms did not fall into the hands of terrorists.

Peskov said evidence about the incident provided by the White Helmets civil defence group could not be considered reliable and added: "We do not agree with these conclusions."

"Immediately after the tragedy no one had access to this region ... any data which the US side or our colleagues from other countries might have had access to could not have been based on objective facts," Peskov told reporters.

The disagreement was unlikely to change the nature of ties between Russia and the United States, Peskov added.

Russia's Foreign Ministry said earlier on Thursday it was too early to accuse the Syrian government of being responsible for the attack in Idlib and said a proper investigation was needed, the RIA news agency reported.