“That’s why this security force of the countries led by Britain and France is so important for the future and I think it’s encouraging that the European leaders are there today,” the former ambassador added.

More than half dozen leaders, including the heads of the UK, France, Italy, German as well as the European Commission and NATO chiefs are at the White House. They are expected to meet with US President Donald Trump and Ukrainian President Volodymyr Zelensky later.

Burns said “pressure has to be applied on Putin by President Trump and the Europeans together