Russian President Vladimir Putin told German Chancellor Angela Merkel in phone talks on Monday that Ukraine needs constitutional reform and also said that Moldova's breakaway Transdniestr region requires measures to end a de facto blockade.

"Discussing various aspects of the situation in Ukraine... Putin stressed the importance of holding constitutional reforms" in Ukraine, the Kremlin said in a statement.

It added they also discussed Moldova's largely Russian-speaking breakaway region of Transdniestr bordering Ukraine and Putin raised "the need to take effective measures aimed at lifting an effective blockade from the outside of this region."