Nicola Sturgeon has said UK foreign policy should be set by Parliament and not Donald Trump after the US, UK and France launched missile strikes against Syria.
Scotland's First Minister said the suspected use of chemical weapons in Douma last week was "sickening" but warned that the latest action risked "dangerous escalation".
Writing on Twitter, she said her first thoughts were with service personnel taking part in the strikes, which targeted infrastructure at three sites connected with the Syrian regime's chemical weapons programme.
Ms Sturgeon said: "Syria's use of chemical weapons is sickening - but the question that the PM has not answered is how this action, taken without parliamentary approval, will halt their use or bring long-term peace.
"Air strikes have not resolved situation in Syria so far - nothing I've heard persuades me they will do so now.
"An international strategy for peace must be pursued - not a course that risks dangerous escalation.
"UK foreign policy should be set by Parliament, not US President."
SNP defence spokesman Stewart McDonald said UK forces were engaged in "gesture bombing with no major international consensus and no long term plan to halt the use of chemical weapons or deliver peace".
He wrote on Twitter: "Most worrying is that she has acted at the behest of presidential tweets and sidelined Parliament.
"What does this new bombing campaign do to help move Syria towards peace? Nothing.
"Instead, it has the potential to dangerously complicate the war, making matters on the ground worse for the people that the strikes are supposed to help. There is no peace strategy.
"This is not a brave or strong decision by the Prime Minister."