Tusk followed NATO chief Jens Stoltenberg who had paid a visit to the Serbian leader on Friday.
The EU Council leader said that the massive influx of refugees crossing into EU borders is "not sustainable for Serbia, EU and ultimately the refugees," as long as Serbia is visa-free within the Schengen area.
Thousands of people crossing Serbia's borders every day not sustainable for Serbia, EU and ultimately the refugees pic.twitter.com/t4KDGNquix
— Donald Tusk (@eucopresident) November 21, 2015
In the meantime, while Europe faces major challenges after the Paris attacks, the President of the European Council urged cooperation with the Middle East and North Africa (MENA) to have a "comprehensive approach" in dealing with the refugee crisis that has hit the EU dramatically.
"There is no one answer to this crisis," he said. "And we cannot rely on any single partner, such as Turkey; we must continue working on a comprehensive approach. This also means working with all partners in Africa, the Middle East, and here in your region."
Tusk stressed that border control should work properly adding "it's our obligation" to ensure secure borders in EU.
"Effective external border control is not the solution to all our problems but is a necessary precondition, even an obligation," he said.
Effective external border control is not the solution to all our problems but is a necessary precondition, even an obligation
— Donald Tusk (@eucopresident) November 21, 2015
Tusk slammed those responsible for the lax border control as such a lack of security poses the primary threat for EU citizens and tourists after the terrorist attacks in Paris last week.
"Due to the lack of effective controls on the external border between the EU and, inter alia, Turkey, some countries in the region are strengthening controls at their borders," he explained. "We cannot condemn them for doing so. However, it would be better for Europe if coordinated and effective actions, aimed at protecting the whole of our external borders, were finally undertaken."
Tusk also added that "EU stands by Serbia" in its intention to join the EU and encouraged the country's Prime Minister Vucic to cooperate to show "support to front-line borders."
EU stands by Serbia. If we are serious about saving Schengen, we must be serious about our support to front-line countries
— Donald Tusk (@eucopresident) November 21, 2015
"We also discussed the accession process of Serbia to the European Union," Tusk noted. "I greatly appreciate Prime Minister Vučić for Serbia's achievements and progress on this path. I hope that the Council will agree to open the first accession chapters very soon."
Historically, the Balkan region has been a strategic point for Europe's security after the disintegration of the Turkish Empire. Nowadays, Serbia has generally been seen to be quite stable in terms of security compared to other neighboring countries so, in the context of finding new ways to resolve numerous EU problems, the country seems to be key for the EU.
