Sanctioned How Russian oligarchs moved their assets after invasion

Biggest leak of financial data from Cyprus raises concerns over EU state's role in money movements by Kremlin allies

- Simon Goodley, Helena Smith, Juliette Garside

Cyprus has vowed to tighten controls on its financial sector as an investigation published by the Guardian and its reporting partners reveals oligarchs transferred hundreds of millions in assets while sanctions loomed after the Russian invasion of Ukraine.

The role of the blue-chip accountants PwC Cyprus and other advisers in managing transactions as Vladimir Putin's forces launched their assault has emerged from Cyprus Confidential, a cache of 3.6m files leaked by an anonymous source to the International Consortium of Investigative Journalists (ICIJ) and Germany's Paper Trail Media, which shared access with the Guardian and other partners.

The largest-ever financial data leak from Cyprus also sheds light on how opaque offshore structures managed by accountants and corporate service providers in the EU member state may have enabled undisclosed payments to an influential western journalist, and potential breaches of rules around football club financing.

The Cypriot government has responded by promising a "zero-tolerance approach" to sanctions violations as it battles to safeguard its status as a financial centre.

A spokesperson said Cyprus was receiving technical support from the British government to create a sanctions implementation unit, with plans to be submitted this month alongside a report on how its authorities investigate and prosecute financial crime. It has also joined an EU cross-border project on making sanctions effective.

The president, attorney general, key cabinet members and officials were briefed last week over progress on implementing tighter controls.