European NATO member countries are developing a secret contingency plan for a possible US withdrawal from the alliance, The Economist reports.

According to the publication, doubts about the reliability of American security guarantees are growing in Europe. Amid statements by US President Donald Trump, European capitals have begun actively preparing for a scenario in which Washington abandons its NATO commitments.

Trump has already canceled the deployment of 4000 American troops to Poland and begun withdrawing 5000 troops from Germany. NATO Secretary General Mark Rutte, according to sources, has effectively banned open discussion of this issue, fearing Washington's reaction.

Trump's threats against Denmark regarding Greenland have caused particular concern.

"The Greenland crisis was a wake-up call for us. We realized the need to develop a Plan B." — the Swedish official said.

A number of European armies are already creating covert command structures capable of conducting combat operations without American assistance and even without the use of NATO's common infrastructure.

The preparation of a plan for an "American exit" reflects a deep crisis of trust within the alliance and Europe's desire to build its own security system.