This is reported by The New York Times.
The article says that when Trump was president, he repeatedly threatened to withdraw the United States from NATO.
In addition, it is specified that the website of the election campaign of the former American leader says that it is necessary to "complete the process of fundamental reassessment of the purpose and mission of NATO," which began during his presidency.
This wording is alarming in European countries, writes NYT.
Earlier, former Pentagon chief Mark Esper said in an interview with MSNBC that Trump, if he wins the next presidential election, could withdraw the United States from NATO, which would mark the end of the alliance.
In addition, he allowed the withdrawal of the US military from a number of other countries around the world.