The UK will increase “lethal and non-lethal aid” to Ukraine amid Russia’s continued military assault, the defence secretary has said.
Ben Wallace said he would set out more details of what the UK and others could do in a statement to MPs on Wednesday.
It will cover equipment for those fighting against Russia and also aid for those affected by the invasion.
But he rejected calls for a no-fly zone over Ukraine, saying it would not halt Russian artillery or missiles.
Ukraine has accused Moscow of preventing safe civilian evacuations as Russian forces continue shelling cities.
Asked if the UK would support Poland if it chose to supply jets to Ukraine, Mr Wallace told BBC Breakfast there was still an ongoing “debate” about whether Poland would do this as it could face Russian “retaliation”.
But the defence secretary said that while Britain could not supply jets directly to Ukraine, it would support Poland in whatever choice it made.
The UK has already pledged a total of £400m in support for Ukraine, as well as providing defensive military equipment and imposing sanctions against Russian banks, companies and individuals.
As Russia’s assault on Ukraine enters its 13th day, Mr Wallace said its forces were “getting more desperate” and “doubling down on brutality”.
Ukraine has begun evacuating civilians from the town of Irpin, near the capital Kyiv, and the northern city of Sumy after Russian and Ukrainian officials agreed to set up humanitarian corridors.
But on Tuesday, Ukrainian officials said Russian forces were shelling an evacuation route out of the besieged southern city of Mariupol.
Ukrainian cities have continued to suffer heavy bombardment from Russian forces, causing several civilian evacuation plans to collapse.
Mr Wallace told BBC Radio 4’s Today programme that Mr Putin was a “spent force in the world” and seemed to have “no limit to the humanitarian grief and murder he can inflict on a country”.
Asked how the war could end, Mr Wallace said one scenario could be if the Russian army becomes “so stuck and defeated” it “turns in on itself and the generals get blamed and then it grinds to a halt”.
He said a second possibility could occur if Russia imposed “its total will” by trying to break the people of Ukraine, because he believed Mr Putin wouldn’t “break the people of Ukraine”.
He added: “The cost to Putin is not just in the invasion, it’s going to be in the decades of occupation, which I don’t think he will be able to sustain.”
Amid criticism of the UK’s visa scheme for Ukrainian refugees, Mr Wallace said the UK could and would do more and ensure the processing of visas was accelerated.
It comes as international diplomatic efforts continue, with Prime Minister Boris Johnson hosting the leaders of Poland, Hungary, Slovakia and the Czech Republic in London on Tuesday for talks on the UK’s support for security in central Europe.