German Chancellor Angela Merkel met with the Dutch king and queen on Tuesday as part of the royal family's three-day state visit to Germany. Details of the conversation were not released.

Earlier on Tuesday, King Willem-Alexander, 54, and Queen Maxima, 50, visited the Reichstag building in Berlin before holding talks with Wolfgang Schäuble, the speaker of the Bundestag, the German parliament. 

They also attendeda session of the Bundesrat, the upper house of the German parliament, where the 16 states are represented.

Willem-Alexander praised border states such as North Rhine-Westphalia and Lower Saxony for helping to take Dutch coroanvirus patietnts in for treatment "when the pandemic was at its height." 

He also urged EU nations to do more to slash CO2 emissions, pointing to the use of hydrogen by Germany and the Netherlands. A lot of additional energy could be produced if the two countries coordinated their efforts to further develop the technology, the Dutch monarch said.

The Dutch royal couple arrived in Germany early on Monday to undertake a trip that was delayed last year in response to the coronavirus pandemic. They met with German President Frank-Walter Steinmeier and visited Germany's national disease control center, the Robert Koch Institute, along with other locations.

On Wednesday, before returning to the Netherlands, the royal couple will visit Berlin's Technical University and the city's new Humboldt Forum cultural center.

jf/msh (AP, dpa)