May said the aim was to deter the Syrian authorities from further use of chemical weapons and to send a message to the wider world that it was unacceptable to use such weapons.
British Prime Minister Theresa May said on Saturday she had authorised British forces to conduct precision air-launched cruise missile strikes on Syria to degrade its chemical weapons capability, saying there was no alternative to military action.
"It was right to take the action that we have done in the timing that we have done", she said. Syrian state media slammed Western strikes on Saturday as illegal and "doomed to fail", after the US, France, and Britain launched a joint operation against the Damascus government.
Shortly after the military strikes were launched, Scotland's first minister Nicola Sturgeon said United Kingdom foreign policy should be set by Parliament and not Donald Trump after the U.S., United Kingdom and France bombed targets in Syria.
Speaking in Downing Street, May said the military strikes should be a "warning to Russia" before holding the Syrian government accountable for the chemical attack.
The opposition leader questioned the prime minister's statement that the Syria attack is "right and legal".
Opposition Labour leader Jeremy Corbyn had said Britain should press for an independent United Nations -led investigation into the suspected chemical attack in Douma rather than wait for instructions from Trump on how to proceed. "Bombs won't save lives or bring about peace". It is about a limited and targeted strike that does not further escalate tensions in the region and that does everything possible to prevent civilian casualties.
He said Britain should not be taking instructions from Washington and putting British military personnel in harm's way. He warned that intervention would lead to a proxy war with Russian Federation which would be "not only unsafe to Britain, but the entire world".
Four Royal Air Force Tornado jets using Storm Shadow missiles had taken part in the attack on a military facility near Homs where it was assessed Syria had stockpiled chemicals, Britain's Ministry of Defence (MoD) said.
"This is the first time as prime minister that I have had to take the decision to commit our armed forces in combat - and it is not a decision I have taken lightly", she said.
Correspondents from the British and world press also asked the prime minister to explain what role can the Parliament play in making a decision to attack another sovereign country. "These risks are a feature of modern confrontation".
The strikes began at 2am BST and destroyed important infrastructure at three sites connected to the Syrian regime's chemical weapons programme, according to the allies.