"I thought frankly it was inappropriate for a president-elect of the United States to be stepping into the politics of other countries in a quite direct manner," Kerry told CNN.
The president-elect focused on European allies in a round of interviews.
President-elect Donald Trump's protectionist rhetoric has alarmed business interests in Germany.
European nations and NATO are setting up centers to identify "fake news", bolstering cyber defenses and tracking use of social media.
Government ministers say new measures will make it easier to deport failed asylum seekers and tag extremists.
The suspect is accused of scoping targets such as the Brandenburg Gate and Reichstag building.
The prospect of having to address questions about Trump days before he enters the White House might have dissuaded the German chancellor.
Anis Amri had contact with preacher Abu Walaa's network, a German security source tells Newsweek.
Angela Merkel's Bavarian allies want intelligence agencies to monitor people as young as 14.
Sanctions tell U.S. allies that America understands and condemns Russian action.
Anis Amri said that ISIS supporters would seek revenge on what he called "crusaders" in Europe.
Among Russia's targets: Germany's parliament and the DNC.
If we allow other people to strip away our values, we will be doing the terrorists' jobs for them.
Several plots have been planned by refugees recently settled in Germany.
Police released the main suspect on Tuesday, citing a lack of evidence.
The truck-ramming in the German capital left at least 12 people dead and 48 injured.