WASHINGTON (Reuters) - The U.S. call for NATO partners to step up funding for the transatlantic alliance is “a fair demand,” German Defense Minister Ursula von der Leyen said on Friday after what she called a positive first meeting with Defense Secretary James Mattis.

German Defence Minister Ursula von der Leyen attends a ceremony to welcome the German battalion being deployed to Lithuania as part of NATO deterrence measures against Russia in Rukla, Lithuania February 7, 2017. REUTERS/Ints Kalnins

Germany and other European powers were unnerved when President Donald Trump during the election campaign accused NATO allies of failing to pay their way, and described the alliance shortly before he took office last month as “obsolete.”

Trump offered some reassurance this week when he told U.S. forces: “We strongly support NATO.”

Von der Leyen said Germany, which spends less than the NATO target of 2 percent of economic output on defense, understood it needed to increase that amount.

“I think it’s a fair demand,” von der Leyen said. “If we want to jointly master the crises in the world, namely the fight against terrorism, and also put the alliance on solid footing, then everyone has to pay their share.”

She told reporters she welcomed an offer from Mattis to deepen the strategic dialogue between the two countries. He had also reiterated his clear and deep commitment to NATO.

Admiring comments from Trump about Russian President Vladimir Putin have raised concerns among some European countries that the United States might relax sanctions imposed against Moscow over its 2014 annexation of Crimea and its support for violent separatists in eastern Ukraine.

Von der Leyen said it was critical that NATO members remained unified. “It is ... very important that we speak with one voice.”

She said she and Mattis agreed that many global problems, including the war in Syria, could not be solved without Russia, but Moscow needed to respect international law and the borders of other sovereign countries.

They had agreed it was important to “continue to act from a position of strength to extend an outstretched hand to Russia and work out our mutual problems at the negotiating table and then solve them.”

The Pentagon said in a statement that Mattis thanked von der Leyen for Germany’s leadership in NATO and acknowledged the role it plays in fighting terrorism, specifically in the coalition fighting Islamic State.

Both look forward to working together at the NATO Defense Ministerial and Munich Security Conference next week, the statement said.

Von der Leyen’s meeting with Mattis lasted for about an hour, twice as long as planned. She was the first European defense minister to visit him at the Pentagon.