The Foreign Secretary said Russian President Vladimir Putin was “humiliating himself on the world stage” as she repeated calls to increase support for Ukraine in defending itself against his invasion, including by easing access to NATO-standard equipment.
Ms Truss will travel to Berlin on Saturday to meet NATO foreign ministers and will push for a “strengthened and modernised” version of the western military alliance, the Foreign Office said.
At the G7 on Thursday, the Foreign Secretary said: “Putin is humiliating himself on the world stage.
"We must ensure he faces a defeat in Ukraine that denies him any benefit and ultimately constrains further aggression.”
She added: “The best long-term security for Ukraine will come from it being able to defend itself.
"That means providing Ukraine with a clear pathway to NATO-standard equipment.”
Thursday’s meeting also saw Ms Truss encourage other ministers to commit to further waves of sanctions for as long as Russian troops stay in Ukraine, the Foreign Office said.
The G7 foreign ministers will be joined by the Ukrainian and Moldovan foreign ministers at another meeting in Schleswig-Holstein on Friday where they will discuss Ukraine.
It follows an announcement from Finland’s leaders on Thursday that they support the country joining NATO, less than 24 hours after signing a historic security pact with the UK.
On Wednesday, Boris Johnson agreed to “mutual security assurances” with both Sweden and Finland, which could see British troops sent to Nordic nations in the event of a Russian invasion.
Finland has previously opted to stay neutral and keep out of NATO for fear of antagonising Russia.
But public support for joining the western military alliance has grown in the country since Mr Putin began his attack on Ukraine in February.
Finland shares an 830-mile land border with Russia, with major city St Petersburg only a few hours drive from the divide.
Liz Truss
Victoria Jones
Vladimir Putin has humiliated himself, according to Ms Truss
Reuters