Turkish President Recep Tayyip Erdogan on Friday told the European Union to stick to past deals on migrants and refugees and aid neighbouring countries as fears of a new exodus from Afghanistan mount.

Rising numbers of Afghan migrants could present "a serious challenge for everyone", Erdogan said in a phone conversation with Kyriakos Mitsotakis, prime minister of neighbouring Greece.

Athens has already said it may send Afghans arriving on its shores back to Turkey, which it regards as a "safe" country for migrants.

Referring to a 2016 deal under which "irregular" migrants landing in the EU can be sent back to Turkey in exchange for aid, Erdogan urged his neighbours to "sincerely live up to their commitments".

Ankara has repeatedly accused EU capitals of failing to hold up their end of the bargain.

Now that it fears increased Afghan arrivals, Brussels should aid neighbouring countries such as Iran to deal with any new mass movements of people, Erdogan said.

"A new wave of migration is inevitable if the necessary measures are not taken in Afghanistan and in Iran," he told Mitsotakis.

Turkey had already spoken to Iran and was toughening up border security, Erdogan added.

The Greek government said in a statement that "the two leaders discussed the necessity of supporting (Afghanistan's) immediate neighbours so Afghans stay as close to home as possible".

Faced with the dramatic Taliban takeover in Kabul, a number of European leaders have called for moves to prevent a repeat of the large numbers of people seeking refuge from Middle East conflicts who reached the EU via Turkey in 2015.