BRUSSELS (Reuters) - German Chancellor Angela Merkel called on European Union members on Thursday to increase their security and defense cooperation because there was no “guarantee of perpetuity” in relations with the United States.

German Chancellor Angela Merkel addresses a news conference at the Museum of Modern Art Grand Duke Jean during an official visit to Luxembourg, January 12, 2017. REUTERS/Francois Lenoir

Europe faced growing challenges within its own borders and in nearby regions, including migration, increasing terrorist threats, the war in Syria, violence in eastern Ukraine and poverty and famine in Africa, she said.

Merkel did not mention President-elect Donald Trump by name but clearly seemed to be referring to new U.S. leader’s campaign trail comment that he would consider a country’s contributions to the NATO alliance before coming to their aid.

“I am convinced that Europe and the EU must learn to take more responsibility in the world in the future,” Merkel told students in Brussels after receiving honorary doctorate degrees from Belgium’s Leuven and Ghent universities.

“Let’s not fool ourselves: From the viewpoint of some of our traditional partners, and I’m thinking of transatlantic ties, there is no guarantee of perpetuity for close cooperation with us Europeans. We have to continue to work at that,” she said.

Merkel said in November that Germany must increase defense spending to work toward meeting a NATO target of 2 percent of gross domestic product (GDP), but played down expectations that it would meet the target the near future.

The EU, which has relied on the United States to guarantee its security for the past seven decades, agreed to take initial steps toward expanded security and defense cooperation at a summit in December.

They called for an overhaul of the way the bloc pays for its military operations abroad by reforming its common-funded Athena mechanism, and a separate fund for pooling and sharing of helicopters, weapons systems and other assets.

Facing criticism at home for her “open door” refugee policy, Merkel also said Europe needed to accelerate its work on an entrance and exit registry to get a better grip on its borders.

She urged EU members to increase their willingness to compromise on issues such as illegal migration, including quicker efforts to return migrants who entered Europe illegally and were denied asylum.