Addressing a news conference in Kyiv alongside Ukrainian President Volodymyr Zelensky, Norwegian Prime Minister Jonas Gahr Stoere said Norway wanted to express its solidarity with Ukraine's fight for survival.
"I'm here to say that Ukraine's fight is not only for Ukraine. This is about some fundamental principles of the world we are going to offer to our children. This is about security in Europe, this is about the fate of your neighbour," he said.
"We will pledge 1 billion euros in support to your country and your people for the remaining part of 2022 and for 2023," he continued. "This war is a breach of international law. ... You have the right to defend yourself and we have the right to help you defend yourself."
Asked whether Norway was willing to increase gas supplies to Europe, Stoere said Norway was already producing gas "at its maximum" but it would do everything it could to provide gas.
Zelensky said pressure needed to be kept up on Russia so the war would end.
He said Russia had used a Soviet-era Kh-22 missile designed to hit aircraft carriers or other large objects to strike a regular nine-storey building - a reference to a strike in the early hours of Friday on an apartment block near Odesa in which Ukrainian officials say at least 16 people were killed.
Russia denies targeting civilians. Asked on Friday whether Russia had struck the apartment building in the resort village of Serhiivka, the Kremlin spokesman said: "I would like to remind you of the president's words that the Russian Armed Forces do not work with civilian targets".