The British Foreign Secretary has accused Russia of war crimes in Syria and called for protests outside the Russian embassy.

Boris Johnson has warned Russia it risks becoming a pariah nation if it continues to bomb civilian targets in Syria, saying international powers must do more to punish Moscow by applying sanctions.

“If Russia continues in its current path then I think that great country is in danger of becoming a pariah nation,” Johnson told parliament on Tuesday, “and if President [Vladimir] Putin’s strategy is to restore the greatness and the glory of Russia, then I believe he risks his ambition turning to ashes in the face of international contempt for what is happening in Syria.”

He said he would “certainly like” to see demonstrations outside the Russian embassy, asking “Where is the Stop the War coalition?”

Russia responded through a series of Twitter posts, saying “Russia’s record on Syria is thousands of freed villages, thousands of tons of humanitarian aid. What’s Britain’s?”

Very unusual call from the Foreign Secretary to hold demonstrations in front of the Russian embassy. New form of British diplomacy? pic.twitter.com/rzxUkGyyrQ

— Russian Embassy, UK (@RussianEmbassy) October 11, 2016

Johnson predicted those responsible for war crimes in Syria would eventually face charges before the International Criminal Court.

“All the available evidence therefore points to a Russian responsibility for the atrocity,” he said, referring to an attack on a humanitarian aid convoy.

“Those who are conducting this bombing and in my view culpable of these crimes should realise that the mills of justice grind slowly but they grind small.”

He called for an investigation into attacks on hospitals, which he said were being targeted with such frequency and precision that it was “difficult to avoid the conclusion that this must be policy”, amounting to a war crime.

Speaking at the end of a three-hour emergency Commons debate on the Syrian crisis, Johnson appeared to reject no-fly zones over areas of the country, saying: “We cannot commit to a no-fly zone unless we are prepared to confront and perhaps shoot down planes or helicopters that violate that zone.

“We need to think very carefully about the consequences.”

But, he added, he was sympathetic to those who made the call, and wanted to work through the options with British allies.