WASHINGTON, April 9 -- A senior US lawmaker has cautioned President Donald Trump against any attempt to withdraw the United States from the North Atlantic Treaty Organization (NATO), calling such a move both unlawful and damaging to national security.

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Representative Raja Krishnamoorthi raised concerns in a letter sent after a closed-door meeting between Trump and NATO Secretary General Mark Rutte at the White House. The congressman criticized the president's recent remarks questioning Washington's commitment to the alliance, warning that such rhetoric could have far-reaching consequences.

Krishnamoorthi stressed that US law clearly prevents a president from unilaterally exiti...