German President Christian Wulff is facing growing calls for his resignation in connection with his alleged attempts to kill a news story on a controversial home loan he received.

Mr. Wulff, an ally of German Chancellor Angela Merkel, is reported to have left an angry voicemail message for the editor of the Bild newspaper threatening legal action if he published the story.

Reporters from another German newspaper also said he threatened them if they pursued the story.

The $600,000 home loan was given to him by the wife of a wealthy businessman while he served as governor of Lower Saxony state.

Mr. Wulff last month apologized for taking the loan, saying he should have disclosed it before becoming president.

Analysts say his potential resignation would reflect badly on Ms. Merkel, who championed his election over a popular opposition candidate.

Mr. Wulff took office in July 2010 following the resignation of former president Horst Kohler, who left office after making controversial statements regarding German soldiers abroad.