Afghan migrants to Europe could double in 2020.

More Afghans than Syrians have migrated to the European Union so far this year, according to official data. The number is expected to double next year.

Turkey's attack on Kurdish-controlled northeast of Syria has led to expectations of a new wave of asylum seekers from Syria. But EU officials say an increasing number of Afghans poses a more immediate problem, especially in the Greek islands where many of them first arrive.

Since the beginning of the year, nearly 17,000 Afghans have crossed the Aegean sea to reach EU shores, the latest data from the EU border agency Frontex show.

Around half of them had been living in Iran before attempting the crossing through Turkey into the...