EU High Representative for Foreign Affairs and Security Federica Mogherini has stressed that EU sanctions related to the annexation of Crimea and to "Russian destabilization of eastern Ukraine" will remain in force.

Delivering a speech during the EP session in Strasbourg on Wednesday, she said that European authorities must maintain there pressure on Russia, and that any future decisions over sanctions should be linked to the situation on the ground.

"As for the sanctions, we agreed that the best thing for now is to stay the course," she said.

However, Mogherini said that it is important to find a way of communication with Russia, for instance, in order to search for a solution to the Ukraine crisis.

She said negotiations were impossible without speaking to one another and, besides, the Ukrainians and the Russians had been communicating between them and Europe should help the Ukrainians in doing so.

The situation is clear: sanctions have been imposed and they have had economic implications. This may not be equally obvious in the political field but political implications may manifest themselves now, Mogherini said in her final remarks at the hearings dedicated to Ukraine.

She said she was speaking not only on her own behalf and recalled earlier statements by European Union President Donald Tusk.

Mogherini indicated that European Parliament deputies involved in the hearings pointed to the importance of the dialogue and added that it could be a link missing on the EU's part.

The EU flexibility should have its limits in opening channels for the dialogue with Russia but it was still necessary to hold the dialogue no matter how difficult that might be, Mogherini said.