WASHINGTON (CBS DC) — The United Nations chemical weapons report on the details of the deadly Aug. 21 attack in Syria “make clear” that the Assad regime carried out the attack, but Russia is unconvinced.

The 41-page U.N. inspectors’ report, which was presented on Monday to the Security Council, found “clear and convincing evidence” that rockets containing the nerve agent sarin were used in the Ghouta suburbs of Damascus.

British, French and American officials said the technical evidence points to the Syrian regime’s culpability.

U.S. Ambassador to the U.N., Samantha Powers stated that “the technical details of the U.N. report make clear that only the regime could have carried out this large-scale chemical weapons attack.”

“It’s very important to note that the regime possesses sarin,” said Power. “And we have no evidence that the opposition possesses sarin.”

But Russia’s foreign minister said it was “too early to conclude,” as Moscow continued to suggest that the Syrian rebels could have been responsible for the chemical weapons use.

“We had a quick glance but were not really able to study the report. We want everybody to treat it as an extremely serious technical matter and we want everybody to look at the report with the eyes of experts,” Russian Foreign Minister Sergey Lavrov said, according to CBS News. “We want the events of the 21st of August to be impartially, objectively, professionally investigated.”

The report included photographs of one of the rockets, which featured lettering from the alphabet used in Russia – Syria’s primary weapons supplier for years, CBS News reports.

“The type of munitions, the trajectories which confirm the analysis that British experts have done about the provenance of where the rockets were fired from, all of that confirms in our view that there is no remaining doubt it was the regime that used chemical weapons,” responded U.K. ambassador to the U.N., Mark Lyall Grant.

United Nations chief Ban Ki-moon condemned the use of sarin gas against civilians, but did not pinpoint the Syrian president for the Aug. 21 attack.

The Obama administration says that more than 1,400 people died in the chemical weapons attack, including hundreds of children.