Russian Foreign Minister Sergei Lavrov has said Britain should "calm down and not get nervous" due to the poisoning of former Russian intelligence agent Sergei Skripal.

"I believe it would be great for everyone, first of all official London, if they stopped getting so nervous – because they obviously are nervous over this whole thing – and calmed down," he said, according to RIA Novosti.

Read alsoRussian denials of spy poisoning "increasingly absurd" - JohnsonLavrov says London hastened to bring charges. "What we are witnessing now is a feverish throwing around the world, persuading partners to stand with Britain on this issue without presenting any facts," he said.

As UNIAN reported, the Russian Foreign Ministry invited foreign ambassadors to Moscow on March 21 to discuss the Skripal case.

Read alsoEU demands Russia urgently hands over all information on Novichok nerve agent programme – mediaOn March 20, 23 Russian diplomats, whom the British government had decided to expel in response to the poisoning of former GRU officer Sergei Skripal and his daughter Yulia, left the UK territory.

Russian ex-spy Sergei Skripal, 66, and his daughter Yulia Skripal, 33, remain critically ill in hospital, after they were found unconscious on a bench in Salisbury, Wiltshire.

The UK government says they were poisoned with a nerve agent of a type developed by Russia called Novichok while the Russian government denies any involvement in the attack.