BERLIN (Reuters) - Turkish President Tayyip Erdogan vowed on Monday to keep Turkey's promises in a migrant deal with the European Union but said the EU was failing to deliver on its side of the bargain.

The EU struck a deal in March to reward Turkey for preventing migrants from crossing to Greece by channeling aid to Syrian refugees in the country, reviving accession talks and scrapping visas for Turks wishing to visit Europe.

The deal has not been finalized.

"I want to say one thing quite clearly: On the refugee issue, we will stand behind our promises," Erdogan told German broadcaster ARD.

"What we have promised to date applies. But a question to the Europeans: have you stuck to your promises?" he asked, saying the EU had failed to provide Turkey with sufficient aid. "The West has unfortunately not been sincere thus far."

(Writing by Paul Carrel; Editing by Tom Brown)