German Chancellor Angela Merkel on Thursday said she had raised concerns over freedom of expression in Turkey in bilateral talks in Ankara with President Recep Tayyip Erdogan.

"I emphasised from my side that in this far-reaching change the separation of powers and freedom of expression must be ensured," Merkel said, referring to Erdogan's plan for constitutional change.

Merkel added she had also passed on concerns over press freedom and the accreditation of German journalists in Turkey.