The Russian attack on Monday, which left at least 11 dead and 64 injured, was launched by Moscow in retaliation for what Vladimir Putin claimed was a terrorist act carried out by Ukrainian special services on a bridge linking Russia with Crimea.
International outcry was swift in the wake of the latest Russian assault, labelled by some as a sign of President Putin’s growing desperation in the face of staunch Ukrainian resistance.
But in a sign of how seriously Western leaders are taking the Russian bombardment, Ms Truss and her G7 counterparts will hold a virtual meeting later on Tuesday, with Ms Truss also expected to call for a full meeting of Nato leaders in the coming days.
The video call will also be attended by Ukrainian President Volodymyr Zelensky, who spoke to the Prime Minister and other world leaders on Monday.
Ms Truss is expected to urge fellow G7 leaders to “stay the course” in the battle against Mr Putin.
“The overwhelming international support for Ukraine’s struggle stands in stark opposition to the isolation of Russia on the international stage,” she is expected to say on Tuesday.
“Their bravery in the face of the most brutal acts of violence has earned the people of Ukraine global admiration.
“Nobody wants peace more than Ukraine. And for our part, we must not waver one iota in our resolve to help them win it.”
G7 leaders are also likely to discuss the global energy crisis sparked by Russia’s invasion, amid plans to introduce a global cap on the price of Russian oil to target Mr Putin’s revenues.
On Monday, Mr Zelensky said Ukraine counts on the UK’s “leadership in consolidating international political and defence support for Ukraine, in particular regarding the protection of our skies”.
Ms Truss has said she is committed to following the example of her predecessor Boris Johnson, who offered ardent support for Ukraine since the start of the Russian invasion.
Ukraine on Monday called for western allies to provide anti-air and anti-missile systems in response to the attacks.
Kyiv was targeted for the first time in months, while Russia also hit civilian areas and energy infrastructure across the country, from Kharkiv in the east to Lviv near the Polish border.
Mr Putin confirmed the strikes were a retaliation for what he called Ukraine’s attack on the Kerch Bridge, a crossing between Russia and the annexed Crimea region that has strategic and symbolic importance.
He said if Ukraine continues to mount “terrorist attacks” on Russia, the Kremlin’s response will be “tough and proportionate to the level of threats”.
Labour leader Sir Keir Starmer joined the condemnation of Russia’s actions, calling the Russian attacks “unjustifiable”.
“The UK is firmly united in condemning Putin’s latest wave of violence and destruction,” he said.