The treaty, which was signed by the UK, US, Japan, Canada, France, Germany and Italy, involves promises to act multilaterally and on a country-to-country basis to offer Ukraine long-term security guarantees.
Speaking at the announcement of the declaration, US President Joe Biden said that the Ukraine declaration will "make clear that our support will last long into the future" and create a path to NATO membership for Ukraine.
"This starts a process by which each of our nations and any other nation who wishes to participate will negotiate long-term bilateral security commitments with and to Ukraine," he said.
"It will be a force of stability in the region and deter against any and all threats," Biden added.
Ukraine's President Volodymyr Zelenskyy welcomed the declaration and said the outcome of the Vilnius summit was "very much needed."
It opens new security opportunities to Ukraine, he said.
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