Berlin -- German politicians warned Monday democracy had been damaged after exit polls for state elections were leaked on Twitter before voting ended, the second time results have recently appeared prematurely.

Exit poll results for key elections in Saarland, Thuringia and Saxony, showing Chancellor Angela Merkel's conservatives had suffered strong setbacks surfaced on the microblogging site around 90 minutes before officially due.

The deputy parliamentary head of Merkel's Christian Union bloc, Wolfgang Bosbach, said the leaking of the results "damaged democracy."

"There is a danger that an election could be falsified," Bosbach told the Koelner Stadt-Anzeiger local daily.

"This is unacceptable," fumed Joerg van Essen, from the pro-business Free Democrats, Merkel's preferred coalition partners.

The federal election commissioner, Roderich Egeler, warned recently that a similar leak could threaten the September 27 general election.

"It would be a worst-case scenario if the exit poll results were to become known before polling stations closed," he said.

Speaking on Monday in Berlin, Egeler said: "It does not matter whether it appears on Twitter or on another information source, the law is clear: no exit poll results can be published before polling stations close."

Anyone breaking this law is liable for a fine of up to 50,000 euros (71,000 dollars), Egeler said, adding he would seek to prosecute people found publishing results ahead of time.

The television stations that broke the news at the correct time vigorously denied they were to blame for the leaks.

A similar leak also occurred during the parliamentary vote to re-elect Germany's President Horst Koehler on May 23.

On that occasion, a handful of lawmakers announced Koehler's victory before the results were officially published.

Experts believe that the premature publication of exit polls can influence election results if they get into the public domain before the final vote has been cast.

For example, if exit polls were to show one candidate ahead by a significant margin, a supporter of that candidate might decide there was no need to go to register a vote.

One of the offending Tweets in this instance came from the Twitter site of Patrick Rudolph, the head of the Christian Democrats (CDU) in the city of Radebeul in Saxony.

He said he had deactivated the account after the affair.

"I don't know who wrote it," he told the online version of Spiegel news magazine.

However, he will be fined 50,000 euros if he was found to have published the results ahead of time.

German politicians have scrambled to harness the power of modern communication for boosting their campaigns.

Merkel has a weekly webcast and her preferred method of communication is sending text messages on her mobile phone. She has a Facebook page with over 15,000 supporters.

Her rival for power, Frank-Walter Steinmeier, has only 5,400 Facebook supporters, apparently reflecting their relatively levels of popularity, as he struggles to close the gap on a double-digit poll deficit.

Nevertheless, the popularity of German politicians pales in comparison to US President Barack Obama's 6.6 million supporters. Even French President Nicolas Sarkozy has 10 times as many Facebook supporters as Merkel.

AFP/Expatica