The head of Nato has said he is “certain” Donald Trump will continue the US’ commitment to the military alliance, days after warning the President-elect not to cut out his European allies.

Jens Stoltenberg, the Nato Secretary General, said: “President-elect Donald Trump stated during the election campaign that he is a big fan of Nato, and I am certain that he will be a President...who will live up to all the commitments of the United States in the alliance.”

He was speaking on Tuesday in Brussels, where he was attending a meeting of EU ministers looking to strengthen defence on the continent, including with cooperation at sea and military exercises.

Obama: No weakening of resolve on global security under Trump

“Europe has to do more, Europe has to step up, Europe has to invest more in defence,” Mr Stoltenberg said.

“I welcome that after many years of cuts in defence spending Europe is now increasing defence spending as a response to a more dangerous and more challenging security environment.”

The Nato Secretary General previously urged Mr Trump to maintain the “indispensable” partnership between Europe and the US, writing in the Observer: “Going it alone is not an option, either for Europe or for the United States.”

During the Republican’s presidential campaign, he said he might think twice about defending Nato allies unless they up increase their defence spending.

“The 28 countries of Nato, many of them aren't paying their fair share,” Mr Trump said in a September debate. “That bothers me.”

Currently, only five allies – including the UK - meet the threshold of spending 2 per cent of GDP on defence, with officials have long calling on member states to boost their budgets.

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The US, which spends roughly 3.6 per cent of its GDP on defence, contributes almost three quarters of Nato’s funds.

Ashton Carter, the outgoing US Defence Secretary, advised concerned partner countries to open discussions with the Trump administration on Monday.

“We're much better at protecting ourselves if we can find a way to work together,” he said.

Mr Trump’s shock victory has triggered widespread speculation about changes to American foreign policy, particularly relating to Russia and the Syrian civil war.

The President-elect and Vladimir Putin agreed to work towards “constructive cooperation” this week, following a warm welcome from the Russian President and applause for the shock election result in the country’s parliament.

The exchanges, following mutual praise throughout Mr Trump’s campaign, have alarmed nations opposing Russia’s backing of President Bashar al-Assad in Syria and intervention in the Ukrainian conflict, including the annexation of Crimea.