By Essi Lehto, Anne Kauranen and Humeyra Pamuk

HELSINKI/WASHINGTON (Reuters) -U.S. Secretary of State Antony Blinken said on Friday the United States was working with Ukraine and other allies to build consensus around the core elements of a "just and lasting peace" to end the war with Russia.

Washington would also encourage initiatives by other countries to bring about an end to the conflict, as long as they uphold the United Nations Charter and Ukraine's sovereignty, territorial integrity and independence.

"We will support efforts – whether by Brazil, China, or any other nation – if they help find a way to a just and lasting peace," Blinken said in a speech.

Still, Washington would continue to support Ukraine militarily as the prerequisite for meaningful diplomacy is that Kyiv is capable of deterring and defending against any future aggression.

"Putin's war of aggression against Ukraine has been a strategic failure," Blinken said.

Speaking in Finland, the NATO alliance's newest member, Blinken said the U.S. would help build a "Ukrainian military of the future".

That meant "a modern air force, integrated air and missile defence, advanced tanks and armoured vehicles, the national capacity to produce ammunition, and the training and support to keep forces and equipment combat ready".

(Reporting by Essi Lehto and Anne Kauranen in Helsinki, Humeyra Pamuk in Washington, writing by Gwladys Fouche, editing by Terje Solsvik)