Russia’s Foreign Minister Sergei Lavrov said Monday the information provided by the US to Russia regarding the use of chemical weapons in Syria was “inconclusive”, RT Russian news network reported. US Secretary of State John Kerry said on Sunday that tests proved positive for use of the sarin gas in Syrian chemical attacks last month.Kerry told NBC's Meet the Press that fresh laboratory tests of blood and hair samples obtained from emergency workers in Damascus tested positive for the gas demonstrating that it was used in the August 21 attack that killed more than 1400 people. Lavrov was speaking during an address to students of the Moscow State University of International Relations, where he accused the West of maintaining a “regime of secrecy.”"If there truly is top secret information available, the veil should be lifted. This is a question of war and peace. To continue this game of secrecy is simply inappropriate," RT quoted him as saying. "We were shown some sketches, but there was nothing concrete, no geographical coordinates or details... and no proof the test was done by professionals... there were no comments anywhere regarding the experts' doubt about the footage circulating all over the internet," Lavrov said.The Russian foreign minister added that, "what our American, British and French partners have shown us before - as well as now - does not convince us at all. There are no supporting facts, there is only repetitive talk in the vein of 'we know for sure.' And when we ask for further clarification, we receive the following response: 'You are aware that this is classified information, therefore we cannot show it to you.' So there are still no facts." Meanwhile, Russian lawmakers have said they will urge the US Congress not to approve military strikes on Syria, the speaker of the upper house of parliament told President Vladimir Putin on Monday. "I think if we manage to establish a dialogue with our partners in the U.S. Congress ... we could possibly better understand each other, and we hope that the U.S. Congress will occupy a balanced position in the end and, without strong arguments in place ... will not support the proposal on use of force in Syria," Valentina Matviyenko said.An unclassified US intelligence report released last week said US authorities have a high degree of confidence that the Syrian government of President Bashar Assad was responsible for the August 21 attack. It stated that this is the strongest position the US intelligence community that vetted the report can take short of confirmation. Meanwhile, China said on Monday it was seriously concerned about any unilateral military action against Syria after US President Barack Obama delayed a military response to last month's chemical weapons attack near Damascus until after a congressional vote.The United States has explained to China its evidence on chemical weapons use in Syria, China's Foreign Ministry spokesman Hong Lei said at a daily news briefing.China has said that no side should rush to pre-judge the results of an investigation by UN chemical weapons experts in Syria, who it said should carry out an objective and impartial investigation in consultation with the Syrian government.