Russia and Iran have thrown down the gauntlet to the US, threatening to respond with military force if any "red lines" are crossed in future.
Tension has been escalating in the wake of a US airstrike on an airfield in Syria, from which it was thought last week's chemical attacks on Khan Sheikhun were launched.
In a joint statement with Iran, the two allies blasted the US for "violating international law" and made it clear they will respond with military force if it should happen again.
The strike was publicly backed by Western allies like France and the UK, and the Foreign Secretary was due to meet Sergey Lavrov to discuss the situation.
However Boris Johnson cancelled his planned trip to Moscow and his upcoming meeting with Mr Lavrov in order to work on a proposal for the G7, to be presented by US Secretary of State Rex Tillerson in the coming days.
It is thought the proposal will demand Russia drop support for President Bashar al-Assad and withdraw its troops from Syria, while extending a tentative offer for the country to rejoin the G7.
The Russian Embassy in the UK has taken a defiant stance on this, releasing a series of memes on Twitter to mock the Foreign Secretary for pulling out of the trip.
Most recently, it posted a poll mocking the potential outcomes of the G7 statement:
The embassy has called Johnson's last-minute cancellation "deplorable" as tension continues to rise over the bombardment and situation in Syria.