EU finance ministers Monday approved one billion euros in financial aid to Ukraine, billing it as a first instalment of a promised nine-billion-euro rescue package agreed by European leaders in May.

"This will give Ukraine the necessary funds to cover urgent needs and ensure the operation of critical infrastructure," said Zbynek Stanjura, the finance minister of the Czech Republic, which holds the EU's rotating presidency.

EU diplomats said the rest of the nine billion euros ($9 billion) was still held up as some member states argued over whether a country at war was in a position to sign on to long-term loans.

"I wish the amount were greater," said one EU diplomat, though adding that talks among member states to release more funds for Kyiv were "on the right track".

The one billion euros announced on Tuesday is in addition to 1.2 billion euros disbursed earlier this year by the European Union, bringing the bloc's total financial aid to Ukraine since the invasion on February 24 to 2.2 billion euros.

Ukraine has said that its budget shortfall is as much as five billion euros per month and that the everyday running of government and public services depends on urgent foreign aid.

Allies have rushed to help Ukraine, with the G7 and others announcing commitments of $29.6 billion in further money for Kyiv, according to the US Treasury Department.

The United States last month transferred $1.3 billion to Ukraine as part of the initial $7.5 billion promised to Kyiv by the Biden administration in May.