A spat erupted after the Canadian Prime Minister was caught on camera seemingly mocking Donald Trump at a Buckingham Palace reception on Tuesday night.
The US President hit back by accusing Justin Trudeau of being "two faced" and failing to meet the alliance's target for defence spending.
France's president also came to blows with the US President, who accused Emmanuel Macron of being "nasty" for calling the alliance's strategies 'brain dead'.
Armed Forces Christian Union's director Rhett Parkinson tells Premier it is unfortunate that "public disagreements" have marked the anniversary of an alliance created to stand for unity.
He highlighted that the "almost unprecedented period of peace that Europe has enjoyed" is largely down to the efforts of Nato.
Parkinson says Christians should "pray for our leaders at this time". Citing Romans 13, he said: "They are appointed as authorities over us."
Amid the rows, Boris Johnson urged the alliance to remain united.
Speaking at the start of a meeting of the North Atlantic Council, Mr Johnson said:
"The fact that we live in peace today demonstrates the power of the simple proposition at the heart of this alliance: that for as long as we stand together, no-one can hope to defeat us, and therefore no-one will start a war."
President Trump has cancelled a planned press conference at a Nato event in Hertfordshire, telling reporters: "We'll go directly back. I think we've done plenty of news conferences."
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