A French-led initiative to restore Europe’s relations with Moscow has led to an offer from Donald Trump to join talks to resolve Russia’s incursion into Ukraine.

Trump has said he is willing to join the so-called Normandy format talks between France, Germany, Ukraine and Russia that may take place at the end of this month, saying he would do so if his presence would help progress.

“I believe the fact that the exchange of prisoners between Russia and Ukraine took place … is a very big step, and a very positive step. If they need me to join, I would join [the talks],” Trump said.

Ukraine and Russia exchanged 70 prisoners on Sunday, an event greeted with joy in Kiev and seen as the most fruitful episode in Russian-Ukrainian relations since the election of the new Ukrainian president, Volodymyr Zelenskiy.

Trump’s remarks follow a rare meeting this week in Moscow between Russian officials and the French foreign minister, Jean-Yves Le Drian, and the defence minister, Florence Parly. The talks have been called a new opening to Moscow by the French.

Le Drian said he would like the next ministerial meeting in the Normandy format to take place this month in Paris, the first such meeting since 2016. Ukraine supports US inclusion in the Normandy format as a way of breaking the five-year deadlock over autonomy and elections in eastern Ukraine.

The French overtures to Vladimir Putin, extending well beyond Ukraine and including new proposals on security, were endorsed on Tuesday by the Russian foreign minister, Sergei Lavrov.

The rapprochement risks leaving the UK out in the cold as the European nation state still most opposed to Russia, in part because of the unresolved issue of Russian use of biological weapons on Sergei Skripal in Salisbury.

Theresa May briefly met the Russian president at the G20 summit in June, but the meeting has not prompted an obvious uplift in British-Russian relations. The UK has always been excluded from the Normandy format, a decision that has been a subject of regret inside the Foreign Office.

Play Video 0:30 Theresa May shares frosty handshake with Vladimir Putin – video

May’s successor, Boris Johnson, now faces the prospect of a pincer between Emmanuel Macron, Angela Merkel and Trump to normalise relations with Moscow, starting in Ukraine.

Some other EU states, notably Poland, housing a bolstered Nato troop presence, will also be unnerved by the warm tone adopted by French ministers, especially on the day that Putin oversaw largely bogus municipal elections in Moscow.

James Nixey at the Chatham House thinktank was sceptical that Putin wanted to be brought in from the cold, at least not on terms recognisable to the EU. “Dialogue for the sake of dialogue – without principles or concrete objectives – is a slippery slope to accommodating Russia’s interests,” he said.

But Macron, entering a new period of diplomatic activism, signalled the pivot to Russia in his set-piece annual speech to French ambassadors on 27 August, saying he wanted to develop a pan-European security structure in co-operation with Russia.

French officials have warned that if there is no European effort to understand Moscow, Russia will simply turn to China. That speech was preceded by a meeting between Putin and Macron on 19 August at Fort de Brégançon.

Macron’s move has provoked a lively debate within France, with some political scientists such François Heisbourg, special adviser to the Foundation for Strategic Research (FRS), warning that Macron’s goals are unrealistic if he thinks he can detach Russia from China.

“The relationship between Russia and China is not the product of western mischief that pushed Moscow to turn to Beijing. The two powers share the same authoritarian vision of the world, where states exercise complete sovereignty over their internal affairs, especially in the field of human rights.”

Bruno Tertrais, the FRS deputy director, writing in Le Monde, said Macron was pursuing a chimera since for 15 years Putin had rejected the west’s decadent values. He added that the whole approach was based on the false premise of the west’s humiliation of Russia.

Aware of the criticism, Le Drian in his talks in Moscow stressed any thaw would be a slow process and that the existing EU sanctions against Russia, due to the invasion of Ukraine and the annexation of Crimea, would not be dropped.

He said: “The release of 70 captured people, including 24 sailors, I believe that this release is the concrete outcome encouraged by France so much.”

Le Drian in his press conference in Moscow insisted he was not being naive, and there were serious points of difference between the French and Russians, including Crimea, interference in western democracies and the downing of Malaysia Airlines flight 17 from Amsterdam by Ukrainian separatists in 2014, killing 298 people.

The Russian insistence that the prisoner swap include Vladimir Tsemakh, the separatist commander in eastern Ukraine and witness to the airliner downing, has enraged the Dutch. He had been seized by the Ukrainians in June, and his release to Moscow now is seen as a sign of the sacrifices Kyiv may be willing to make to normalise relations with Russia in eastern Ukraine.