French President Francois Hollande said Friday that US President Donald Trump's administration poses "challenges" for Europe.

"Let's speak very frankly, there are challenges, there are the challenges the US administration poses to our trade rules, as well as to our ability to resolve conflicts around the world," Hollande said in Berlin.

French President Francois Hollande arrived in the Central African Republic on Friday, nearly three months into a difficult mission to stop the sectarian bloodshed sweeping the country.

His high-security visit to Bangui caps a week that saw the French parliament extend Operation Sangaris and another 400 extra troops arrive in the deeply unstable former French colony.

Queen Beatrix of the Netherlands announced Monday that she would abdicate in favor of her son Crown Prince Willem Alexander after 33 years in power.

"It is with the greatest of confidence, that I will hand over the throne on April 30 to my son, Willem Alexander, Prince of Orange," Beatrix said in a televised address, using the official title of the heir apparent.

French President Francois Hollande attended the Rio Earth summit last week with minimum protection after his bodyguards left their firearms in Paris, sources close to the case said Tuesday.

The elite GSPR unit which protects the French leader normally travels with a briefcase that contains the weapons, but on their arrival in Brazil on June 19 the bodyguards realized that the weapons had stayed behind at Hollande's office in the Elysee palace.

The Dutch government said Saturday it was freezing its contacts with Iran, decrying the hanging of an Iranian-Dutch woman in the Islamic republic as an "act committed by a barbarous regime."

"The Netherlands has decided to freeze all contacts with Iran" after obtaining confirmation of Zahra Bahrami's execution from Iran's ambassador to the Netherlands, foreign ministry spokesman Bengt van Loosdrecht told Agence France Presse.