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British Foreign Secretary Boris Johnson has canceled a planned trip to Russia because of fast-changing developments in Syria — prompting a mocking tweet and a Russian official to take a dig at the West.

Amid rising tensions between Moscow and Washington, Johnson said Saturday the situation in war-torn Syria had "fundamentally" changed following a chemical weapons attack on civilians and the U.S. airstrikes targeting a military airfield.

In a statement released by the British Foreign Ministry, Johnson condemned Russia’s continued defense of the Assad regime “even after the chemical weapons attack on innocent civilians.”

He said he would no longer visit Moscow on Monday and that his priority now was to continue contact with the United States and other nations in the run up to the G7 meeting next week.

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The U.S. fired 59 Tomahawk cruise missiles at Syria overnight Thursday in response to what it believes was a chemical weapons attack earlier in the week that killed more than 100 people.

British Foreign Secretary Boris Johnson has decided not to visit Moscow as planned on April 10, 2017. FACUNDO ARRIZABALAGA / EPA

At least six people were killed, Syria claimed, but the Pentagon said civilians were not targeted and the strike was aimed at a Syrian military airfield in Homs.

The strike completed a policy reversal for President Donald Trump — who once warned America to stay out of the conflict — and drew angry responses from Damascus and its main ally, Russia.

Trump on Saturday tweeted his congratulations to the American military for "representing the United States, and the world, so well in the Syria attack."

Congratulations to our great military men and women for representing the United States, and the world, so well in the Syria attack. — Donald J. Trump (@realDonaldTrump) April 8, 2017

Johnson said he had spoken to Secretary of State Rex Tillerson, who will visit Moscow next week as planned following the two-day G7 summit. He said Tillerson would be able to deliver a “clear and coordinated message to the Russians.”

Related: Syria Missile Strikes: What Can Trump Do Now?

But responding to Johnson’s announcement, Russian Foreign Ministry representative Maria Zakharova described his reasons as “absurd,” according to Russian news agency Interfax.

“It looks like our Western colleagues live in their own reality,” she said, adding that “we always stood for building stable relations on firm international legal grounds. Unfortunately, stability and coherence have stopped being the landmark of the Western foreign policy long ago."

.@BorisJohnson cancelled his visit to Moscow: theatrics for lack of argument? Safer in G7 pack? Listen to our soft power response: pic.twitter.com/PjSa5psT6p — Russian Embassy, UK (@RussianEmbassy) April 8, 2017

The Russian Embassy in Britain also tweeted a response, along with a video of Russian conductor Valery Gergiev conducting Pytor Illyich Tchaikovsky’s "Ouverture Solennelle 1812."

The tweet read that Johnson "cancelled his visit to Moscow: theatrics for lack of argument? Safer in G7 pack? Listen to our soft power response."