President Donald Trump refused to rule out accepting Russia's annexation of Ukraine's Crimea region when he meets his Kremlin counterpart Vladimir Putin next month.

Asked by reporters yesterday whether he was considering -- as has been reported -- dropping Washington's opposition to the 2014 land grab, Trump said: "We're going to have to see." Trump's refusal to reaffirm the long-standing US opposition to Russia's intervention in Ukraine will dismay European allies ahead of next month's NATO summit.