WikiLeaks founder Julian Assange has been served with a letter saying he has to present himself to a London police station, according to sources.
The letter apparently told Assange to present himself at London's Belgravia police station at 11.30am on Friday.
Assange has been inside the Ecuador embassy in London since last week seeking political asylum.
He is trying to avoid extradition to Sweden, where he is wanted for questioning about alleged sex offences.
It is understood that officers from the Metropolitan Police's extradition unit delivered a note to the embassy on Thursday morning.