The German economy grew by 1.5 percent in 2018, the weakest rate in five years and markedly slower than the previous year, preliminary data showed on Tuesday, in a sign that exporters in Europe's largest economy are being hit by trade tensions.

German companies are struggling with a cooling of the global economy and tariff disputes triggered by U.S. President Donald Trump's "America First" policies. The risk that Britain will leave the European Union without a deal in March is another uncertainty.

The preliminary gross domestic product estimate published by the Federal Statistics Office was in line with market expectations and compared with a growth rate of 2.2 percent in 2017.