New Delhi, Jan. 24 -- UK Prime Minister Keir Starmer and Britain's Prince Harry slammed President Donald Trump's claims suggesting that NATO troops did not serve on the front line in Afghanistan.

Under NATO's founding treaty, member countries are committed to a collective-defense obligation, outlined in Article 5, which considers an attack on one member as an attack on all. This clause has been invoked only once, following the September 11, 2001 attacks on New York and Washington, when NATO allies pledged their support for the United States, according to Reuters. Throughout much of Afghanistan conflict, the US-led forces operated under NATO command.

"I consider President Trump's remarks to be insulting and frankly appalling, and I'm not...