The UK foreign secretary said she feared Russian president Vladimir Putin was willing to use the “most unsavoury means” to obtain his objective.
Truss also said she feared the conflict could become “very bloody” and escalate into a conflict with Nato.
The cabinet minister told Sky News: “We’ve already seen the response from the Russian government. We’ve seen the actions taken despite all of the warnings about the severe cost of this conflict in terms of humanitarian costs, in terms of cost for the Russian state.
“This could all be the beginning of the end for Putin and I fear that he is determined to use the most unsavoury means in this war.
“But he should be aware that the International Criminal Court is already looking at what is happening in Ukraine and there will be serious consequences for him personally and for the Russian government.”
“This could all be the beginning of the end for Putin and I fear that he is determined to use the most unsavoury means in this war.”
– UK foreign secretary Liz Truss
It comes amid reports that Russian troops have entered Ukraine’s second-largest city Kharkiv.
Air raid sirens have been going off in Kyiv this morning and the Ukrainian president has rejected negotiations with Russia in Belarus – saying the country has been used for attacks.
Western countries have agreed to remove some Russian banks from the Swift international banking system.
Huge numbers of people have continued to flee Ukraine for neighbouring countries, including Poland and Moldova.
The UK is under pressure to rip up bureaucracy to provide sanctuary for those fleeing Ukraine.