The European Union on Saturday deplored victims in Friday's clashes between pro- and anti-government protesters in Ukraine's Black Sea city of Odessa, urging "everyone" to exercise utmost constraint.

Saying the EU is "deeply saddened" by the tragic loss of human lives, the European External Action Service in an official statement said an "independent" probe should be launched to ascertain the cause and those responsible should be brought to justice.

"All political forces must now assume their responsibility and engage in a peaceful and inclusive dialogue to find a joint way out of the crisis," the statement said.

The EU urged reinforced efforts to implement the Geneva Joint Statement of April 17, which calls for de-escalation of tension in Ukraine.

More than 40 people were killed and over 170 others injured when pro- and anti-government protesters clashed on Friday in Odessa, according to local officials.

Among the dead, mostly pro-Russia protesters, 30 were choked to death when radicals set fire to a trade union building, while eight others died as a result of jumping out of windows to escape the burning building.