The 2016 US presidential elections kicked off earlier in the day, with voters choosing between Democratic nominee Hillary Clinton, her Republican rival Donald Trump and several other contenders.
"The transatlantic partnership will, of course, in any case remains a necessary condition for us, including for cooperation with NATO," Merkel told reporters when answering a question on the ongoing election.
Tuesday is an important day for democracy, she stressed, noting that Germany will anxiously await the results of the elections in the United States.
The TTIP free trade agreement, which has been negotiated since 2013, involves the creation of a free trade zone between the European Union and the United States.
The TTIP agreement has drawn severe criticism for the lack of transparency in the negotiations as well as for the tremendous power it would potentially give to international corporations.