Contradicting the Pentagon, which earlier said that the Russian forces were notified in advance of the strike using established deconfliction line, United States Secretary of State Rex Tillerson told reporters that Russia was not alerted.
"There were no discussions or prior contacts, nor had there been any since the attack with Moscow," The Guardian reported Tillerson as saying.
Earlier in the day, the Pentagon confirmed it used a hotline for minimising the risk of aerial combat between U.S. and Russian jets in eastern Syria to alert Moscow of the strike against the Syrian Government.
"Russian forces were notified in advance of the strike using the established deconfliction line. US military planners took precautions to minimise risk to Russian or Syrian personnel located at the airfield," Pentagon spokesman Captain Jeff Davis said.
"We are assessing the results of the strike. Initial indications are that this strike has severely damaged or destroyed Syrian aircraft and support infrastructure and equipment at Shayrat airfield, reducing the Syrian government's ability to deliver chemical weapons. The use of chemical weapons against innocent people will not be tolerated," he added, citing "the strike was a proportionate response to Assad's heinous act and that it was intended to deter the regime from using chemical weapons again."
More From This Section
Hours after launching a military strike on the Syrian government target in response to the gas attack, Trump called on all 'civilised nations' to stop the slaughter and bloodshed in Syria. He also asserted that Assad "choked out the lives of innocent men, women and children."
"Tonight I ordered a targeted military strike on the airfield in Syria from where the chemical attack was launched. It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons. There can be no dispute that Syria used banned chemical weapons, violated its obligations under the chemical weapons convention, and ignored the urging of the UN security council," he said.
"Years of previous attempts at changing Assad's behaviour have all failed and failed very dramatically. As a result the refugee crisis continues to deepen and the region continues to destabilise, threatening the United States and its allies. Tonight I call on all civilised nations to join us in seeking to end the slaughter and bloodshed in Syria, and also to end terrorism of all kinds and all types," he added.
On Trump's orders, U.S. warships launched between 50-60 Tomahawk cruise missiles at the Syria Government airbase where the warplanes that carried out the chemical attacks were based, U.S. officials said.
Trump had famously said the chemical attack on Syria's Idlib province affected his deeply and tranformed his thinking about the Syrian president Bashar al-Assad.
Dozens of people, including at least ten children, were killed and over 200 injured as a result of asphyxiation caused by exposure to an unknown gas on Tuesday.
The death toll is said to be at least 67, according to activist al-Diab, while the U.K.-based Syrian Observatory for Human Rights has reported it to be 58.
The High Negotiations Committee claimed the death toll could be as high as 100 with up to 400 injured.