By Justyna Pawlak and John Irish

BRUSSELS G7 countries will announce on Wednesday an international framework that would pave the way for long-term security assurances for Ukraine to boost its defences against Russia and deter Moscow from future aggression, officials said.

Ukrainian President Volodymyr Zelenskiy was meeting leaders of the 31-member alliance at the NATO summit, after they declared on Tuesday that Ukraine's future lay inside the alliance but rebuffed his call for a timeline for membership.

Without getting entry while the war with Russia continues - given that NATO's Article 5, which says that an attack on one member is an attack on all, could push the alliance into war with Russia - Ukraine has sought current and long-term security commitments.

NATO has assiduously abstained from giving military assistance to Ukraine as an organisation, to avoid entering a direct conflict with Russia, and is keen to continue leaving that to member states and others.

Britain, France, Germany and the United States, known as the Quad, have been negotiating with Kyiv for weeks over a multilateral text that would create a broad framework for member states, encompassing elements including modern advanced military equipment, training, intelligence-sharing and cyberdefence.

"The joint declaration, expected to be signed by all members of the G7, will set out how allies will support Ukraine over the coming years to end the war and deter and respond to any future attack," the British government said in a statement.

The G7, which comprises the United States, Germany, Japan, France, Canada, Italy and Britain, as well as the European Union, will meet on the margins of the NATO summit later on Wednesday to announce the initiative.

Countries such as Poland and Romania are likely to also sign up on Wednesday to the framework, which would be open to other countries to make their own bilateral commitments, officials say.

"As Ukraine makes strategic progress in their counteroffensive, and the degradation of Russian forces begins to infect Putin's front line, we are stepping up our formal arrangements to protect Ukraine for the long term," British Prime Minister Rishi Sunak said.

Diplomats said in return for the assurances, Ukraine would also pledge to push through governance and judicial reforms.

(Additional reporting by Andrew Gray and Steve Holland; Editing by Alex Richardson)