May made the remarks while addressing parliament on Monday, where she stressed
that the strikes were carried out to "further prevent the use of chemical
"We have not done this because President Trump asked us to do so," she added.
Early on Saturday, the US, Britain and France carried out a string of airstrikes against Syria over a suspected chemical attack against Douma. Washington and its allies blamed Damascus for the suspected assault.
The Syrian government has strongly denied the allegation, calling on Organization for the Prohibition of Chemical Weapons (OPCW) to send a fact-finding mission for investigations.
Meanwhile, UK opposition Labour Party leader Jeremy Corbyn has reiterated his stance that British premier is "accountable to the parliament - not to the whims of the US president."
Corbyn further stressed that the attacks were illegal and violated UN Security Council's charter.
"There is no more serious issue than the life and death matters of military action," he added.
"It is right that parliament has the power to support or stop the government from taking planned military action," he further noted.