The European Union has reassured Britain that it stands in solidarity with its ally over the Salisbury nerve agent case.
It comes after Britain accused Russia of the nerve gas attack on British soil.
European Commission Vice President Valdis Dombrovskis said Britain had EU support.
"We are very much concerned with the situation, also the findings the UK has so far. Of course the UK can count on EU solidarity in this regard," he said.
Belgium MEP Guy Verhofstadt tweeted, "We stand shoulder to shoulder with the British people. It must be made clear that an attack against one EU & NATO country is an attack on all of us".
Nigel Farage, the MEP for South East England, said Britain's Prime Minister should organise a meeting with Russian president Vladimir Putin soon.
"I think the next step to me is that she (Theresa May) ought to demand a meeting with Putin, in Oslo or Reykjavik, somewhere neutral like that, because there are a lot of things to talk about," he said.
Estonian Green MEP Indrek Tarand in Strasbourg added that pressure could be put on Russia using financial sanctions.
She said: "We can obviously use the financial sanctions to people who are suspects or involved in those kind of activities, I think that it would be the right time to consider."