Ukraine is too corrupt to join NATO, the US is set to tell leader Volodymyr Zelensky in a major blow to his nation's security ambitions.

The defence bloc will request at its annual summit next week, in Washington DC, that Ukraine takes 'additional steps before formal membership talks progress', a senior US official told the Telegraph.

Zelensky has been pushing for NATO ascension after Russia's brutal invasion ends to protect itself from future invasion, as the pact compels its members to militarily defend allies if they are attacked.

But corruption, among other issues, has been a major thorn in the Ukrainian leader's side, blocking further relations with the West from developing.

In 2022, after Ukraine formally applied for EU ascension, the EU Commission wrote of Ukraine that while 'preventing and combating corruption has been particularly high on the Ukrainian reform agenda since the Revolution of Dignity' in 2014, 'corruption remains a serious challenge.'