Swedish prosecutors are set to give an update on the rape investigation against WikiLeaks founder Julian Assange, who has been holed up in Ecuador's embassy in London for four years.

The news conference with prosecutors Marianne Ny and Ingrid Isgren comes ahead of an investigative report on the case, scheduled to be aired Wednesday by Swedish broadcaster SVT.

Assange is wanted for questioning over a rape allegation stemming from his visit to Sweden in 2010. He denies the accusation.

SVT posted a preview clip where Assange declines to discuss the case, saying the "proper place for that is in a formal statement to the Swedish prosecutor. ... That's something that she has avoided for six years."

Ecuador says it has approved a Swedish request to question Assange at the embassy.