Angela Merkel has warned that she will not agree with new US president Joe Biden on everything, and that even with a new administration in Washington, Europe will have to take on more military and diplomatic responsibility in the world.

“Don’t think that from tomorrow there will only be harmony between us,” she told reporters just a day after Mr Biden’s inauguration. “There will also be arguments about how best to do things for our two countries.”

Mr Biden’s entry into the White House was met with huge relief in Germany, which was routinely attacked by his predecessor Donald Trump over everything from its large current account surplus and relatively low defence spending to its support for the Nord Stream 2 gas pipeline from Russia to Europe.

But Ms Merkel emphasised that she did not always see eye-to-eye with Mr Biden either, saying that when he was vice-president they had clashed on the wisdom of selling weapons to Ukraine.

Despite her note of caution, the chancellor expressed broad optimism about the future of the transatlantic relationship, saying there would be “much more scope for political agreement” with Mr Biden than with his predecessor.

She nodded to the executive orders he signed on his first day in office, which halted the US withdrawal from the World Health Organization and brought it back into the Paris climate deal, saying Germany looked forward to working with America on both health and climate issues. “Co-operation [will] rest on a broader foundation of common beliefs,” she said.

But she said the same strategic challenges Europe faced under President Trump had not gone away. “Europe will on the whole have to take on more responsibility, both in military and diplomatic terms,” she said. “The good news is that both Germany and the EU are prepared to do so.”

Some irritants are expected to remain in the US-German relationship. The US has, for example, angered Germany by imposing sanctions on Nord Stream 2 — a project which Ms Merkel noted is opposed by both Democrats and Republicans in Washington. The chancellor said such extraterritorial sanctions are “not OK”.

European critics of the pipeline — who say it will increase the continent’s reliance on Gazprom gas at a time when the Kremlin is rolling back civic freedoms in Russia — have called on Berlin to pull the plug on the project in view of the Kremlin’s arrest of Alexei Navalny, the prominent critic of Russian president Vladimir Putin.

Ms Merkel on Thursday said she had not changed her mind about Nord Stream 2, which she has always backed. But she suggested she would be in favour of a wide-ranging discussion with the US about Europe’s energy relationship with Russia, in which “we put everything on the table”.

“We will have to talk about what economic relations with Russia in the gas sector are acceptable and which aren’t,” she said, noting that the US also buys oil from Russia. “We need to talk about whether we don’t have any more trade with Russia in the area of gas, or what level of dependency is tolerable.”