The Conservative and Labour parties have traded blows in recent days over alleged Russian interference in U.K. politics as the country’s general election enters its final week.

The main opposition center-left Labour Party has used a leaked U.K.-U.S. trade document as evidence that the ruling center-right Conservative Party intends to privatize the National Health Service (NHS) after Brexit.

The document has played a central part in Labour’s election efforts as it was the party that created the NHS and supports nationalization of key public utilities. The Conservatives have denied they intend to sell the NHS.

Read more: UK election hit by allegations of Russian interference