NATO's chief is urging the alliance's 29 countries to set aside a festering trans-Atlantic row over trade, climate and the Iran nuclear deal, amid concern that the tensions will undermine the military alliance.
In an editorial in Tuesday's Guardian newspaper, NATO Secretary-General Jens Stoltenberg said "the ties that bind us are under strain."
He said "we must continue to work hard to settle our differences - and where differences persist, we must limit any negative impact on our security cooperation."
Stoltenberg's message comes less than a month before U.S. President Donald Trump meets with his NATO counterparts in Brussels. Stoltenberg says NATO has overcome divisions before and can do so now.
Trump humiliated his partners at a summit last year, publicly berating them for failing to spend enough on defense.
"Since the alliance was created almost 70 years ago, the people of Europe and North America have enjoyed an unprecedented period of peace and prosperity. But, at the political level, the ties which bind us are under strain," Stoltenberg wrote.
"There are real differences between the United States and other allies over issues such as trade, climate change and the Iran nuclear agreement.
"These disagreements are real and they won't disappear overnight. In fact, nowhere is it written in stone that the transatlantic bond will always thrive. That doesn't, however, mean that its breakdown is inevitable. We can maintain it, and all the mutual benefits we derive from it."
Stoltenberg's article came ahead of next month's NATO summit and his meeting with British Prime Minister Theresa May on Thursday.
The NATO chief's remarks followed a verbal attack by U.S. President Donald Trump on German Chancellor Angela Merkel, while defending his government's policy of separating children from their parents at the U.S. border, saying the U.S. would not become a "migrant camp under my watch."
On Twitter, Trump also claimed that "the people of Germany are turning against their leadership as migration is rocking the already tenuous Berlin coalition".
On Monday, Merkel was given a two-week deadline by her ultra-conservative coalition partner to adopt stricter migration and asylum rules in agreement with other EU member states.
- NATO SPENDING BY MEMBER STATES
Trump in January 2017 sharply criticized NATO in an interview with German daily Bild, calling the organization "obsolete".
He argued that NATO had failed to address terrorism and today's challenges.
"NATO had problems. Number one it was obsolete, because it was, you know, designed many, many years ago. Number two -- the countries aren't paying what they're supposed to pay," he had said.
A threshold to spend 2 pct of the GDP by the year 2024 has been agreed by all member states, a target which is still to be reached by all member states.
Stoltenberg praised the U.S. under Trump for its renewed commitment to NATO but also pointed out that cuts in defense spending among the NATO allies have been reversed across the board.
"The United States and Canada are stepping up their commitment to Europe's security. In fact, since coming to office, the Trump administration has increased funding for the US presence in Europe by 40 percent," Stoltenberg wrote.
"The last U.S. battle tank left Europe in 2013 but now they're back in the form of a whole new U.S. armored brigade," he wrote.
"This isn't a one-way street. European allies, with the U.K. in the vanguard, are stepping up too-spending billions more on defense and taking responsibility for Euro-Atlantic security alongside their North American allies."
Stoltenberg wrote: "It is-and has always been-in our fundamental interest to stand together on defense."
"And that is as true now as ever. Because we face the most unpredictable security environment in a generation: international terrorism, the proliferation of weapons of mass destruction, cyber-attacks-and, of course, a Russia which has used force against its neighbors, which tries to meddle in our domestic affairs, and which seems to have no qualms about using military-grade nerve agents on our streets.
"Our achievements side-by-side are unprecedented. So as long as we stand together, even if the road does indeed get rough, it will always lead in the right direction: peace and security for our nations and our nearly one billion citizens."
