EU summit to send 'clear message' on ex-spy poisoning

EU leaders will discuss a nerve agent attack on a Russian ex-spy in Britain at a Brussels summit next week, with president Donald Tusk saying the bloc would send a "clear message".

The decision to add the Sergei Skripal case to the summit agenda on March 22 is another display of solidarity to the government of British Prime Minister Theresa May despite divisions over Brexit.

Tusk, who will host the summit as head of the European Council, said on Twitter he had phoned May today "to prepare (a) clear message of the EU on #SalisburyAttack".

Former double agent Skripal and his daughter Yulia were left critically ill by the attack in the city of Salisbury, southwestern England, on March 4, which May has blamed on Russia.

"Skripal will be discussed Thursday evening next week. At this stage, I expect summit conclusions on it," a European source told AFP on condition of anonymity.

The incident comes at a particularly tense time for UK-EU relations, as the two sides are locked in Brexit talks ahead of Britain's departure from the bloc in March 2019.

Western leaders have strongly backed Britain in the wake of the attack and supported its claim that Russia is "culpable".

It has already been raised in recent days at the UN Security Council and in the NATO military alliance, which described it as the "first offensive use of a nerve agent on Alliance territory since NATO's foundation."