Russian President Vladimir Putin has warned that any additional strikes by Western powers against Syria will "inevitably lead to chaos in international relations."
Putin made the remark in an April 15 telephone conversation with Iranian President Hasan Rohani, according to a release by the Kremlin.
The two presidents reportedly agreed that the April 14 air strikes by the United States, the United Kingdom, and France were a violation of international law and "have brought serious harm to the chances of a political settlement in Syria."
The air strikes came in response to a suspected Syrian chemical attack that killed dozens of people last week.
U.S. Ambassador to the United Nations Nikki Haley told the Security Council on April 14 that the military strikes were "justified, legitimate, and proportionate."
"I spoke to [U.S. President Donald Trump] this morning and he said, 'If the Syrian regime uses this poisonous gas again, the United States is locked and loaded'," she said.
"When our president draws a red line, our president enforces the red line," she added.
The wave of missile strikes was the most significant attack against President Bashar al-Assad's government by Western powers in seven years of Syria's brutal civil war.
The UN Security Council on April 14 rejected an effort by Russia, a key ally of Syria, to denounce it as an unjustified "aggression" against a sovereign state.
At the Security Council emergency meeting, Russia's UN envoy, Vasily Nebenzya, read out a quote from President Vladimir Putin accusing the allies of "cynical disdain" in acting without waiting for the results of a chemical-watchdog investigation into the alleged chemical attack in the former rebel-held town of Douma on April 7.
Inspectors from the Organization for the Prohibition of Chemical Weapons (OPCW) arrived in the Syrian capital, Damascus, on April 14 and were expected to begin their investigation at the site of the alleged chemical attack on April 15.
Nebenzya accused the United States, Britain, and France of "hooliganism" and of "demonstrating a blatant disregard for international law."
Syrian envoy to the UN Bashar Jaafari claimed that the Douma attack was a "masquerade" mounted by rebels.
Assad said the strike would increase Syria's resolve to "fight and crush terrorism in every inch" of the country.
Meanwhile, the Syrian Army announced on April 14 that eastern Ghouta, the region near Damascus where Douma is situated, had been cleared of the last rebel fighters and was fully retaken.
In northern Syria, the Britain-based Syrian Observatory for Human Rights said an explosion rocked an area where pro-government Iranian fighters and allied Shi'ite militias were based.
The monitoring group said the source of the blast on April 14 was not immediately clear and could have been caused by an air strike or an incident.
Trump praised the military strike on Syria as a "perfectly executed" operation and said it was aimed at ending the use of such weapons of mass destruction.
The White House said Trump spoke to British Prime Minister Theresa May and French President Emmanuel Macron later on April 14.
The White House said the leaders agreed the air strikes in Syria "were successful and necessary to deter" the future use of chemical weapons.
Speaking on the BBC on April 15, British Foreign Secretary Boris Johnson said that the strikes were about saying "enough is enough" over what he called the "barbaric" use of chemical weapons.
Johnson also insisted that the action would not "turn the tide" of the conflict and was not about regime change.
In Damascus, Russia’s news agencies reported that Assad told a group of Russian lawmakers that the Western missile strikes were an act of aggression.
They quoted the legislators as saying Assad was in a "good mood" and accepted an invitation to visit the Siberian region of Khanty-Mansi. It was not clear when the visit would occur.
At a Pentagon briefing on April 14, Lieutenant-General Kenneth McKenzie said three sites that are "fundamental components of the regime's chemical-weapons infrastructure" were struck.
The three sites included the Barzah chemical-weapons research and development center near Damascus that was hit by 76 missiles and "destroyed."
McKenzie said the Him Shinshar chemical-weapons storage facility near Homs was hit by 22 missiles.
He added that the Him Shinshar chemical-weapons bunker facility near Homs was targeted with seven missiles and was "successfully hit."
McKenzie said the operation was "precise, overwhelming, and effective,” adding it will set Syria’s chemical-weapons program back "for years."