The leaders of the European Union and Turkey held talks by videoconference on Friday, ahead of next week's EU summit that will address the bloc's relations with Ankara.

"We underlined the importance of sustained de-escalation and of further strengthening confidence-building to allow for a more positive EU-Turkey agenda," European Commission President Ursula von der Leyen said in a statement after the discussion.

"The presidents also exchanged views on the situation of Syrian refugees hosted in Turkey as well as the wider regional situation including Libya and Syria," the EU statement added.

The video call between Turkish President Recep Tayyip Erdogan, von der Leyen and European Council President Charles Michel was arranged to try to improve ties between Brussels and Ankara that had become fraught in recent years.

Why are EU-Turkey ties strained?

The issues include: Erdogan's power grab and the rollback of democracy, Turkey's involvement in conflicts in Libya, Syria and — indirectly — Nagorno-Karabakh, a spat over energy exploration in the eastern Mediterranean, and accusations that Ankara has used Syrian refugees staying in the country as a political pawn to win EU concessions.

EU foreign ministers are expected to discuss a joint report on relations with Turkey on Monday ahead of the summit of EU heads of state and government later in the week.

Leaders are expected to discuss updating a 2016 migrant deal under which Turkey has curbed entries into Europe in exchange for financial support from Brussels.

How does Erdogan see ties improving?

Erdogan told the video call that Turkey expects next week's discussions to "pave the way for concrete work," on rebuilding ties, his office said.

The Turkish president said he hopes the EU report will reflect "objective and constructive views" on how Turkey-EU relations can move forward.

Erdogan called on Brussels not to allow Greece and Greek Cypriots to gang up on Turkey, and instead urged increased dialogue to resolve the eastern Mediterranean dispute.

During Friday's talks, the three leaders also discussed the possibility of a visit to Turkey soon, according to an EU statement.

Back from the brink

Turkey and Greece have been at odds over maritime boundaries and natural gas reserves in the eastern Mediterranean, which saw Brussels threaten Ankara with sanctions, although these have since been put on hold.

Turkey had sent navy warships to protect its research vessels operating in the disputed waters, but has since softened its stance.

The EU is also closely following UN efforts to restart peace talks over Cyprus in which Turkey is a key player.

mm/rs (AFP, dpa)