He noted that the attack was not authorized by the United Nations and was in violation of international law thus being "an act of military aggression".
"We do not know what may happen next. But I know for sure who benefited from this act of aggression — Daesh, because [the attack] gave them [terrorists] a free rein," Medvedev said.
"And what we see is that the new US administration's first step in the Syrian issue was a strike against government troops. This means that this is not a fight against terrorists but a fight against the Syrian leadership. Whether Americans like it or not, but that is a legal political power," he elaborated.
The prime minister said that further escalation of the Syrian conflict may lead to the destruction of the state and partial victory of terrorists.
"It is obvious that further escalation will lead to the destruction of the Syrian state, its disintegration and a partial victory of terrorists. Such a scenario contradicts our plans and Russia will work in this direction," Medvedev said.
He described the chemical incident in Syria's Idlib province as "a well-planned provocation" from which Washington might have benefited.
"Everything that has happened recently in Syria, including the military attack by the United States, absolutely does not benefit the settlement of the situation. What happened in Idlib is a large and well-planned provocation from which, probably, the US administration benefited." Medvedev called for an investigation and warned against sticking labels [on Bashar Assad's government].
On April 7, the United States launched 59 Tomahawk cruise missiles at the Syrian military airfield in Ash Sha’irat. US President Donald Trump said that the attack was a response to the alleged chemical weapon use in Syria's Idlib province on April 4, which resulted in the death of over 80 people, an incident which Washington blames on the Syrian government.
The Russian Defense Ministry said on April 5 that the airstrike near Khan Shaykhun by the Syrian air force hit a terrorist warehouse that stored chemical weapons slated for delivery to Iraq, and called on the UN Security Council to launch a proper investigation into the incident.
Russian President Vladimir Putin said on April 6 that groundless accusations in the chemical weapons incident in Syria's Idlib were unacceptable before the investigation into the matter had been carried out while Foreign Minister Sergei Lavrov on Saturday criticized the US missile attack as a violation of the international law.
Iranian Supreme Leader Ayatollah Ali Khamenei described the US missile strike against the Syrian airfield as a strategic mistake.
After the missile attack, the Russian Defense Ministry suspended a point-to-point communications link with the US military under the memorandum of understanding on de-confliction in Syria.
The ministry said the Russian air group in Syria was protected by S-400 and Pantsir-S1 air defense systems on a round-the-clock basis.
In an exclusive interview with Fox Business on April 12, US President Donald Trump blamed the current situation in Syria on Moscow's support for country's Assad, calling the Syrian leader "an animal."