Explainer-What did Trump say about NATO funding and what is Article 5?

FILE PHOTO: Former U.S. President and Republican presidential candidate Donald Trump speaks during the National Rifle Association (NRA) Presidential Forum at the Pennsylvania Farm Show Complex & Expo Center, in Harrisburg, Pennsylvania, U.S., February 9, 2024. REUTERS/Leah Millis

BRUSSELS (Reuters) - Former U.S. President Donald Trump raised a storm of criticism from the White House and top Western officials for suggesting he would not defend NATO allies who failed to spend enough on defence and would even encourage Russia to attack them.

Here are the answers to some key questions about NATO, the comments by Trump - who is running for another term in the White House in November and leading President Joe Biden in some polls - and their implications.