Nato is considering ending its recent practice of holding annual summits, six sources told Reuters, a move that could avoid a potentially tense encounter with US President Donald Trump in his final year in office.

Trump’s administration has engaged repeatedly in scathing criticism of many of the US-led defence alliance’s 31 other members, most recently berating some for not providing more help to US military operations against Iran.

The frequency of Nato ‌summits has varied over the alliance’s...