UPDATE 1-Germany's Hypo Real Estate unveils fresh writedowns

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FRANKFURT, Aug 13 (Reuters) - Embattled German investment bank Hypo Real Estate HRXG.DE unveiled further writedowns on Wednesday as its profit tumbled in the second quarter of the year.

The bank, which recently won JC Flowers as a major investor, said it would write down the value of its debt investments by a further 145 million euros ($216 million).

"The next months will continue to be challenging for the entire financial sector," said Chief Executive Georg Funke, unveiling a sharp fall in pretax profit to 40 million euros from 320 million a year earlier.

"The fact that market prospects are still uncertain means that it is almost impossible to make reliable forecasts," he added.

Analysts polled by Reuters had on average expected pretax profit of 39 million.

New business in commercial real estate financing was 2.6 billion euros in the second quarter -- less than a third of what it had been a year earlier. New public sector finance business, however, was, at 11.3 billion euros, more stable.

Hypo, which finances the building of office blocks and shopping centres, surprised investors at the start of the year with writedowns despite earlier playing down the threat of the credit crunch.