The foreign secretary is planning to give a speech in the capital Kiev, where she is expected to underscore the principle of national sovereignty and call on Russia to pursue diplomacy.
The Foreign Office said Ms Truss will visit Ukraine, Poland and Germany, where she is expected to reiterate the UK’s call for Russia to abide by its commitments, respect Ukraine’s sovereignty and warn Moscow that pursuing a path of aggression will lead to severe economic sanctions.
On the trip, Ms Truss will meet her Ukrainian and Polish counterparts, Dmytro Kuleba and Zbigniew Rau, in a demonstration of unified support for Ukraine's sovereignty.
On Saturday, the foreign secretary will then attend the Munich Security Conference where the Foreign Office said she will strengthen security ties with some of the UK’s major strategic allies.
In a planned speech in Kiev, Ms Truss is expected to say: “We want to live in a world where people are in charge of their own future, free from aggression and coercion, where security is truly indivisible and where nations respect the sovereignty of others, and live up to their commitments.
“That means working together with our friends in Ukraine and beyond to face down threats wherever they are across the world.
“I urge Russia to take the path of diplomacy. We are ready to talk. But we are very clear — if they decide to continue down the path of aggression, there will be massive consequences bringing Russia severe economic costs and pariah status.”
Russia could drag out the crisis over Ukraine for weeks – or even months – in an attempt to undermine Western unity, Ms Truss warned on Wednesday.
Ms Truss said it was essential not to be “lulled into a false sense of security” by Moscow’s claims it was beginning draw back its forces from the borders of its southern neighbour.
The UK foreign secretary's visit comes after Russian President Vladimir Putin said Moscow was ready for talks and emphasised the need for the West to grant his main demands.
Russia’s Ministry of Defence claimed troops are returning to base following the conclusion of military exercises near the border, with units crossing out of Crimea on Wednesday.
But Nato Secretary General Jens Stoltenberg said “we have not seen any withdrawal of Russian forces”.
UK Defence Secretary Ben Wallace said on Wednesday that Russia had “a very significant force … that would overwhelm Ukraine should it be deployed” and reiterated advice from the Foreign Office for British citizens to “seek to either leave or avoid travel to Ukraine”.
Prime Minister Boris Johnson said on Tuesday that the UK’s embassy in Kiev will remain open, despite the risk of an invasion and the decisions made by allies to close their diplomatic missions in the country.