LONDON — A British judge granted Julian Assange bail on Tuesday but the WikiLeaks founder will remain in custody for at least another 48 hours after Swedish prosecutors said they would challenge the decision.

Assange, a 39-year-old Australian, has already spent a week in a U.K. jail following his surrender to police in a Swedish sex-crimes investigation. He denies any wrongdoing and his lawyers say he plans to fight Sweden’s extradition request.