The North Atlantic Treaty Organisation (NATO) Secretary-General, Jens Stoltenberg, called on Europe to take a positive stance during the talks on Turkey at the European Union summit.
"There are differences that we have to address, but at the same time we have to realise that Turkey is part of the alliance and part of the Western family," said Stoltenberg at a joint press conference with Portuguese Prime Minister Antonio Costa.
"We must all have a positive attitude while considering differences with Turkey at the summit of European leaders," added Stoltenberg.
He stressed that the NATO had set up a mechanism for resolving the conflict between Turkey and Greece based on this positive approach.
The NATO official described the situation in the Eastern Mediterranean as "difficult", noting that the issue had also been discussed at last week's meeting of NATO foreign ministers.
"We must all have a positive attitude while considering Turkey's differences at the summit of European leaders," he added.
Stoltenberg stressed that the NATO had set up a mechanism for resolving the conflict between Turkey and Greece based on this positive approach. Turkey, he continued, is an important ally within the NATO and plays a pivotal role in the fight against Daesh on its borders with Syria and Iraq.
It also hosts a large number of Syrian refugees and has fallen victim to the highest number of terrorist attacks, he continued.