Brussels (AFP) - Eurogroup head Jeroen Dijsselbloem warned Thursday that Europe was "on its own" after protectionist Donald Trump took over as US president, but said it could be an opportunity to strengthen the EU.

Trump has upset officials in Europe by dubbing the US-led NATO alliance obsolete, hailing Britain's vote to leave the European Union and backing the break-up of the bloc.

"I've made my mind up that in the coming years we are on our own, which may be a good thing," Dijsselbloem said as he arrived for talks in Brussels with eurozone finance ministers.

Without the United States, its historic protector and ally, Dijsselbloem suggested the way forward was closer economic and defence ties between European nations.

"Maybe that's what Europe needs -- to really work together in a better and more productive way, to sort out its own problems, to strengthen its own economic balance, its own defence situation," said Dijsselbloem, who is also Dutch finance minister.

"It's up to us now, which could be a good thing."

Also at the talks, European Economic Affairs Commissioner Pierre Moscovici dismissed speculation by Trump's expected nominee as US ambassador to the EU that the eurozone was on the verge of collapse.

"The euro is not going to collapse, (not) in 18 months, (nor) in 10 years, (nor) 20 years," said Moscovici, who is also a former French finance minister.

Ted Malloch, Trump's reported choice for the new Brussels envoy, told the BBC he would "short the euro" -- betting on the currency's value falling.

Moscovici said the priority must be to "strengthen" the monetary union, adding that it was "no use trying to divide the Europeans."

"We will disappoint those who see us as already dead. We should all reflect on (the words of 19th century US novelist) Mark Twain: The news (reports) about my death are ... premature."