The presidents of France and Germany have sharply condemned US foreign policy under Donald Trump, saying respectively that Washington was “breaking free from international rules” and the world risked turning into a “robber’s den”.

In unusually strong and apparently uncoordinated remarks, Emmanuel Macron and Frank-Walter Steinmeier warned the postwar rules-based international order could soon disintegrate.

“The US is an established power, but one that is gradually turning away from some of its allies and breaking free from the international rules that it was until recently promoting,” Macron told France’s diplomatic corps at the Élysée Palace on Thursday.

“Multilateral institutions are functioning less and less effectively,” the French president said. “We are living in a world of great powers, with a real temptation to divide up the world.”

He said France “rejects the new colonialism and new imperialism – but also vassalage and defeatism. What we have achieved for France and in Europe is a step in the right direction. Greater strategic autonomy, less dependence on the US and China.”

The comments came as EU leaders – torn between the needs to defend international law and to keep the US onboard as a vital economic partner and defence ally in Ukraine and beyond – struggle to agree a coordinated response to Washington’s actions.

While neither president said so directly, both were widely presumed to be referring to last weekend’s US raid on Caracas and capture of the Venezuelan leader, Nicolás Maduro, and to Trump’s repeatedly stated aim of taking control of Greenland.

The EU foreign policy chief, Kaja Kallas, said on Thursday that the bloc was weighing its response if US plans to acquire Greenland materialise. “The messages we hear are extremely concerning,” she said. “If this is a real threat … then what would be our response?”

Nato ambassadors in Brussels also held a discussion about the Arctic territory, where they reportedly agreed the alliance should strengthen Arctic security. “No drama,” a senior Nato diplomat told Reuters. “Lots of agreement that Nato needs to accelerate its development of [a] stronger deterrence presence in the region.”

Specific steps remain undecided, though some nations suggested modelling efforts on Nato’s eastern flank missions, Baltic Sentry and Eastern Sentry, which use flexible multinational deployments and advanced tech such as drones and sensors to monitor land and sea.

Steinmeier, speaking on Wednesday night at a symposium in Berlin to mark his 70th birthday, said global democracy was at risk. The former German foreign minister said Russia’s invasion of Ukraine was a watershed, but subsequent US behaviour marked a second “epochal rupture”.

There had been a “breakdown of values by our most important partner, the US, which helped build this world order”, said the president, whose role is largely ceremonial. “It is about preventing the world from turning into a robber’s den, where the most unscrupulous take whatever they want.”

Steinmeier said the erosion of the world order had already reached an advanced stage. Smaller, weaker states risked becoming “completely defenceless”, and entire regions could be treated “as the property of a few great powers”.

He said European security policy needed to be revised as a consequence. “We must not be weak,” he said, adding that Germany could only play a role “if we are taken seriously, also militarily”, so this was “the goal we have to achieve”.

Macron in his speech also stressed the importance of safeguarding academic independence and “a controlled information space, where opinions can be exchanged completely freely, but where choices are not made by the algorithms of a few”.

He said the EU’s Digital Markets Act (DMA), which covers competition, and the Digital Services Act (DSA) on content moderation – which the US has denounced as an attempt to “coerce” its tech companies into censorship – “must be defended”.