Attempts to "freeze" the conflict in Ukraine where it is are "absolutely wrong" and should be "called out," British Prime Minister Rishi Sunak has said.
Sunak was answering former Labour leader Jeremy Corbyn, who made the case for a ceasefire.
The prime minister said he could not disagree more with Corbyn, an independent member of parliament (MP), and said a temporary suspension of fighting would not be a "just and lasting peace" for Ukraine.
The exchange took place in the Commons after Sunak delivered a statement on his meeting with G7 leaders in Japan.
Calling for the UK to back international calls for a ceasefire in Ukraine, Islington North MP Corbyn asked: "The prime minister mentioned the United Nations in the context of his remarks about Ukraine, and he will obviously be aware the United Nations has quite rightly condemned the Russian invasion of Ukraine.
"Could he make any comments on the calls made by [UN] General Secretary [António] Guterres to attempt to negotiate a ceasefire supported by [South African] President [Cyril] Ramaphosa and supported by the pope and what comment would he make about the statement made this morning by President Lula [da Silva] of Brazil?
"He's right, that a ceasefire is not peace, but any peace process has to be started by a ceasefire, otherwise this war will go on and get worse and worse."
The prime minister replied: "I could not disagree with him more. A ceasefire is not a just and lasting peace for Ukraine. Russia has conducted an illegal and unprovoked invasion.
"It has committed heinous war crimes and the right and only response to that is for Russia to withdraw its forces from Ukraine, and all plans masquerading as peace plans, that are in fact attempts just to freeze the conflict where it is, are absolutely wrong and they should be called out."
Earlier, in response to Scottish National Party (SNP) Westminster leader Stephen Flynn, the prime minister said other countries had agreed to the principle of a "just and lasting peace" being based on the UN charter and territorial integrity and sovereignty.
He said: "Whilst many people may have ideas at what peace in Ukraine looks like, a ceasefire is not a just and durable peace and we will keep ensuring that the peace Ukraine has is one that it deserves and one that is truly just and lasting."
In his speech to the Commons, Sunak also said the UK and its Western allies would stand with Ukraine "for as long as it takes."
Speaking of Ukrainian President Volodymyr Zelensky, he said: "His attendance at the G7 summit was a historic moment. When [Russian President Vladimir] Putin launched his war, he gambled that our resolve would falter, but he was wrong then and he is wrong now.
"Russia's military is failing on the battlefield, their economy is failing at home as we tighten the stranglehold of sanctions, and the image of the G7 leaders standing shoulder to shoulder with President Zelensky in Hiroshima sent a powerful message to the world – we will stand with Ukraine for as long as it takes."
