BERLIN, March 22 (Reuters) - Germany's Frank-Walter Steinmeier used his first speech as president to issue a stark warning to Turkish President Tayyip Erdogan, saying he risked destroying everything his country had achieved in recent years and damaging ties with its partners.

Ankara has been embroiled in a row with Berlin and other European capitals over campaigning among the Turkish diaspora for a referendum on granting Erdogan greater powers.

"The way we look (at Turkey) is characterised by worry, that everything that has been built up over years and decades is collapsing," Steinmeier said on Wednesday in his inaugural speech in the largely ceremonial role.

"President Erdogan, you are jeopardising everything that you, with others, have built," he said, adding that he would welcome "credible signs" to ease the situation.

NATO ally Turkey has repeatedly accused Germany of using Nazi tactics to ban ministerial appearances and has caused anger in Germany by holding German-Turkish journalist Deniz Yucel.

"But end the unspeakable Nazi comparisons!" Steinmeier said. "Do not cut the ties to those people who want partnership with Turkey! Respect the rule of law and the freedom of media and journalists! And release Deniz Yucel."

(Reporting by Madeline Chambers; Editing by Paul Carrel) ((Madeline.Chambers@thomsonreuters.com; +493028885230; Reuters Messaging: ann.chambers.reuters.com@reuters.net))

Keywords: TURKEY REFERENDUM/GERMANY