Members of the pro-business FDP reacted with disappointment to Sunday's early results which put them at just 4.7 percent. This means they may not stay in the Bundestag and will no longer be Chancellor Merkel's junior coalition partner.

It would mark the first time the FDP has not made it into the Bundestag since it was created.

Rainer Brüderle said Sunday in Berlin that as the FDP's top candidate he accepts responsibility for the poor outcome, which he described as a "dark hour" for the party.

"We hope we will still be able to make it [over the 5 percent threshold]," he said of the early results adding that, "This does not mark the end of the party. It will be tough but we will keep working."

The FDP has consistently polled at about 5 percent throughout the campaign, which is the minimum required to send lawmakers to the Bundestag. However, their failure to clear 5 percent in Sunday's general election means Merkel will now be forced to reach out to a different partner as she seeks to build a parliamentary majority with her CDU party. This could force her into another uneasy grand coalition with the Social Democrats.

In the 2009 election the FDP earned 14.6 percent of the vote and became the junior coalition partner to Merkel's CDU party.

The FDP suffered major losses in state elections losing representation in several state assemblies. Party head Philipp Rösler, pictured above, has faced criticism within his own ranks.

Last week during election in the German state of Bavaria, the Free Democrats failed to win representation and earned just 3.3 percent, far below the 5 percent threshold. As a result, the FDP appealed to voters to use their second vote - which ultimately is the one that decides the balance of power in Germany's parliament - to try and secure their spot as a junior coalition partner.

In Germany, voters may cast two ballots. The first is for a single direct candidate in their constituency, while the second is for a political party and its list of candidates nationwide.

For more information about Germany's election, please visit DW's election special page.