The UK and US are at loggerheads over Ukraine’s relationship with Nato, after American officials said its path to membership should not be described as “irreversible”, it has been reported.

Washington is reportedly concerned about plans to give Volodymyr Zelensky new assurances on Nato membership at a summit next month.

The UK has backed a suggestion by some European member states to describe Ukraine’s path to join the alliance as “irreversible” in a joint statement, CNN reported.

But the US believes the language should be toned down, describing the process as a “well-lit bridge” to membership with no concrete timeline.

At last year’s Nato summit in Lithuania, members agreed that Ukraine’s “future is in Nato”, but declined to offer a deadline for it to join the alliance.

The Telegraph understands this year’s meeting, to be held from July 9 in Washington DC, will not see any further assurances on the timeline but will involve new security guarantees for Ukraine from members.

US officials are reportedly concerned that describing the path to joining the alliance as “irreversible” would be unacceptable to some members, including Hungary.

The UK is thought to have sided with some eastern and central European countries, who are among the most supportive of Ukraine’s membership.

A central European diplomat told CNN they were frustrated with America’s “ambiguity and procrastination” over the membership question, as Ukraine’s protracted war with Russia continues.

There is support among some members to “fast track” Ukraine’s membership at this year’s meeting – giving greater assurances to Kyiv that it will eventually be protected by Nato’s collective defence clause.

However, some other members say that Ukraine has yet to meet the criteria for entry by reforming its government.