Johnson ordered the preparation of relevant papers for a meeting that starts today. He stressed these should be "very punitive sanctions".
The Russian embassy in London suggested that if Moscow received an ultimatum from western powers this week it could lead to "real war".
Russia and Iran warned jointly yesterday that they would "respond with force" if there were further US attacks in Syria.
Earlier Boris Johnson canceled his visit to Russia due to the recent developments in Syria.
He noted London regrets Russia's continued support for the Assad regime even after a chemical airstrike against innocent civilians.