"I believe that these debates may be on the table today," Ratas said. "I sincerely hope that the European Council will adopt a joint and strong position on this issue today," he added.

"We fully condemn the poisoning attack. We trust our partners, we trust the information that the United Kingdom give us," Ratas said.

Ratas pointed out that he decided to call off his visit to Russia planned as part of the celebrations of the 100th anniversary of the Republic of Estonia due to recent international tensions in connection with the poisoning of former Russian intelligence officer Sergei Skripal. Ratas would have attended a cultural event of the Estonian community in the Russian city of Krasnoyarsk.

President of the European Council Donald Tusk said in his invitation to the heads of government that following the Salisbury attack, the union should not only express its full solidarity with the United Kingdom, but also draw "operational conclusions."

"I therefore propose we strengthen our resilience to chemical, biological, radiological, and nuclear-related risks, including through closer cooperation among the EU institutions, our member states, and NATO. We should also continue to bolster our capabilities to address hybrid threats, including in the areas of cyber, strategic communication and counter-intelligence," Tusk said.

Former Russian military intelligence officer Sergei Skripal and his daughter Yulia were poisoned with a nerve agent in Salisbury, United Kingdom, on March 4. Both are still in hospital in critical condition. Skripal is a British citizen, his daughter a Russian citizen.

According to the British government, all signs point to the involvement of Moscow in the poisoning, and the Russian government has refused to clarify how the use of Novichok, a nerve agent developed for military purposes in the Soviet Union, was possible in the United Kingdom. The British government has said that Russia had the ability, motive, and will to commit the attack.

Prime Minister Theresa May appealed to the solidarity of EU members following the Salisbury attack. She said in Brussels on Thursday that the "Russian threat does not respect borders."

"It is clear that the Russian threat does not respect borders, and that indeed the incident in Salisbury was part of a pattern of Russian aggression against Europe and its near neighbors," May said in her doorstep statement to journalists.

Following the incident, the UK expelled 23 Russian diplomats and their family members, altogether some 80 people. High-level contacts with Moscow were suspended.