"I think that nobody needs the attack in the form it is spoken about and with such results. It very much looks like training before you start shooting in earnest," Mikhail Gorbachev told Latvia's Baltkom radio station.
The former president of the Soviet Union described the attack as an "unacceptable" move which he warned "would lead to nothing good."
His statement came a day after it was reported that the US, the UK and France launched more than 100 cruise and air-to-surface missiles on a spate of civilian and military targets in Syria in response to an alleged chemical attack in the Damascus suburb of Douma on April 7.
According to the Russian Defense Ministry, a total of 71 missiles out of 103 were intercepted by Syria's air defenses while approaching their targets; Russian air defense units did not participate in the interception as no missile entered their areas of responsibility.
The Syrian Foreign Ministry has slammed the US British and French strikes as a "brutal, barbaric aggression," a statement that was echoed by Russian President Vladimir Putin who called the strikes an aggression against a sovereign state.
Earlier, US President Donald Trump tweeted that Russia should brace itself for "nice and smart" US missiles which he said would be launched on Syria. Shortly after he backtracked on the remarks in a follow-up tweet, saying that he didn't know when the strike on Syria will take place.