Senior Russian lawmaker says that a U.S. strike on Syria could trigger a direct military clash between Russia and the United States.

Vladimir Shamanov, a retired general who heads the defense affairs committee in the lower house of parliament, said in televised remarks Tuesday that a U.S. strike in Syria could hurt Russian servicemen and trigger Russian retaliation.

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He said that Russia has "the necessary means for that and the Americans and their allies know that quite well."

Shamanov emphasized that a retaliatory Russian strike could target U.S. navy ships and aircraft. He added that the use of nuclear weapons is "unlikely."

Last week, a chemical attack on a rebel-held town in Syria's eastern Ghouta killed dozens of people, a medical relief organization and rescue workers reported, and Washington said it would demand an immediate international response if the reports were confirmed.

Medical relief organization Syrian American Medical Society said 41 people had been killed, with other reports putting the death toll much higher. The Syrian Observatory for Human Rights said at least 80 people were killed, including around 40 who died from suffocation. The civil defense rescue service, also known as the White Helmets, put the death toll as high as 150 on one of its Twitter feeds.

Meanwhile, Russian-backed Syrian state denied government forces had launched any chemical attack as the reports began circulating last Saturday and said rebels in the eastern Ghouta town of Douma were in a state of collapse and spreading false news.