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...