Germany's trade surplus widened in May, official data showed Monday, just days after a stormy G20 summit that saw clashes with the United States over protectionism.

Exports from Europe's largest economy grew 1.4 percent compared with April adjusting for seasonal effects, reaching 107.9 billion euros ($123.02 billion), according to federal statistics office Destatis.

With imports gaining 1.2 percent to 87.6 billion euros, Germany's trade surplus -- the amount its exports outweigh its imports -- grew to 20.3 billion euros in May, compared with 19.7 billion in April.

Using a year-on-year comparison, exports were 14.1 percent higher than in May 2016.

The trade surplus reached around 250 billion euros across the full year last year.

The surplus is a major source of tension between Germany and historically close allies in the US and the European Union.

Critics accuse Berlin of failing to import and invest enough to allow other countries to profit indirectly from its success.

Alongside China, Germany has been one of US President Donald Trump's most frequent targets for complaint, featuring as a key argument in his "America First" trade policy.

For now, "the protectionist talk of the new US administration has had no impact so far on German exports to the US," ING Diba bank analyst Carsten Brzeski pointed out.

America accounts for almost nine percent of all German sales abroad, making Washington a major reason why "the success of the German economy is endangered by political risks like never before," said Joachim Lang, director of the Federation of German Industry (BDI).

G20 leaders' joint statement on trade signed Saturday "did not break the dangerous worldwide trend towards protectionism," he continued. 

Meanwhile, Britain's decision to quit the EU "has clearly left its mark," Brzeski said, noting that Britain was the destination for just 6.9 percent of all German exports between January and March -- well below the 7.5 percent recorded over the whole year in 2015