British Prime Minister Theresa May has authorised British forces to conduct precision strikes against Syria to degrade its chemical weapons capability.
"This is not about intervening in a civil war. It is not about regime change," May said in a statement.
"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."
The strikes were conducted with the United States and France.
May said while the strike was targeted at Syria, it sent a message to anyone who used chemical weapons.
Britain has accused Russia of being behind a nerve agent attack on a former Russian spy in England last month, a charge Moscow has rejected.
"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.
"I have done so because I judge this action to be in Britain's national interest. We cannot allow the use of chemical weapons to become normalised - within Syria, on the streets of the UK, or anywhere else in our world."