Augusto Santos Silva said the ambassador, Paulo Vizeu Pinheiro would return this week, probably tomorrow to Moscow as had the EU ambassador who the European High Representative of the European Union for Foreign Affairs, Federica Mogherini, has also ordered back to the Russian capital.

Mr Santos Silva said the return of the European representative was one of the reasons for Portugal deciding to return its ambassador to Moscow.

The Portuguese government recalled its ambassador on 27 March following the nerve agent attack on the former Russian spy Serguei Skripal in Salisbury (UK), which London blames on Russia.

Federica Mogherini also recalled the EU representative from Moscow, but most European countries, except Portugal and five other states, chose to expel their Russian ambassadors.

The poisoning of the former spy and his daughter on British soil led to one of the worst crises in relations between Russia and the west since the cold war and caused an unprecedented wave of Russian diplomats being expelled from western states.