Boris Johnson has urged anti-war activists to stage demonstrations outside the Russian Embassy in London over the country's involvement in the Syrian civil war.

The British Foreign Secretary issued the call to protest as he addressed MPs during an emergency debate on the bombing of the besieged city of Aleppo.

"I would certainly like to see demonstrations outside the Russian Embassy, where is the Stop the War coalition?" Johnson said.

The senior Conservative also warned that Russia could become a "pariah nation" if its military continued to support President Bashar al-Assad's regime.

"If Russia continues on its current path, I believe that great country is in danger of becoming a pariah nation," Johnson said.

"And if President [Vladimir] Putin's strategy is to restore the greatness and the glory of Russia, then I believe he risks seeing his ambition to ashes in the face of international contempt for what is happening in Syria."

The Foreign Secretary also claimed "all the evidence" pointed to Russian being responsible for a deadly airstrike on aid convoy near Aleppo in September.

But despite his calls for "innovative" solutions to get aid to the city's inhabitants and a recommitment to sanctions on Assad and Russia, Johnson warned about implementing a Libyan-style no-fly zone.

"We cannot commit to a no-fly zone unless we are prepared to confront or shoot down planes or helicopters that violate that zone, and we need to think very carefully about the consequences," he said.

Instead, the foreign secretary called for a new ceasefire between the warring factions in Syria and for the West to help create a "political solution" to the conflict.

The United Nations Children's Fund (Unicef) has branded the situation as "dire", while former International Development Secretary Andrew Mitchell has compared Russia's involvement to the Nazi bombing of Guernica during the Spanish Civil War.

"When it comes to incendiary weapons and munitions such as bunker buster bombs and cluster bombs, the UN makes it clear that the systematic use of such indiscriminate weapons in densely populated areas amounts to a war crime," he told MPs yesterday.

"We are witnessing events that match the behaviour of the Nazi regime in Guernica in Spain."

UPDATE: 12 October, 8:57 BST

"Today's parliamentary debate on Syria is depressing," a spokesperson for the Russian Embassy said. "The speeches of those who participated in the discussion contradict the logic of all previous decisions of the International Syria Support Group as well as UN Security Council resolutions (Britain is a member of both).

"USA and other members of the Western coalition failed to separate Jabhat Al-Nusra from the so-called "moderate opposition" they work with.

"The jihadists keep terrorizing the civilians and fighting, rejecting cease-fire and humanitarian aid deliveries.

"Britain's logic implies putting an end to fighting terrorists and their allies. So, UK was not ready to support the plan of UN Special envoy Staffan de Mistura, aimed at alleviating the humanitarian situation in Aleppo.

"Our logic is different. Fight on to destroy the jihadists, sparing the civilians.
Syria is going through the hard process of defeating terrorists. Pity that the British parliamentarians placed themselves on the wrong side of history this time."

Conservative Party Conference
Foreign Secretary Boris Johnson Toby Melville/ Reuters