Defence Secretary Ben Wallace has admitted he is ‘’not optimistic’’ a Russian incursion into Ukraine can be stopped.
The Cabinet minister, who was at talks in Germany, said there was still ‘’a chance’’ an invasion could be halted.
However, he added: ‘’I’m not optimistic.’’
The former officer also confirmed would soon meet with Russian defence minister Sergei Shoigu in Moscow.
The US has rejected Russia’s demand for a veto on Ukraine’s membership of the Nato military alliance.
US Secretary of State Anthony Blinken offered no concessions - but said that he was offering Russia “a serious diplomatic path forward, should Russia choose it”.
But Russian President Vladimir Putin’s chief spokesman Dmitry Peskov said “there isn’t much reason to be optimistic” about a solution.
Moscow needed time to analyse the US response and would not “rush into assessments”, he added.
The US has also threatened to halt the opening of a key pipeline that would send Russian gas to Western Europe if an invasion goes ahead.
Nord Stream 2 would run from Russia to Germany and officials in Berlin have said the project could face sanctions if Russia attacks.
It comes after Foreign Secretary Liz Truss said the UK is not ruling out support for personal sanctions against Mr Putin.
Ms Truss made the comments after US President Joe Biden suggested moving to penalise the Russian president could be an option.
Russia denies it is planning an attack but the build-up of tens of thousands of troops on Ukraine’s borders has heightened fears of an invasion.
