LONDON – WikiLeaks will step up its publication schedule of secret documents, founder Julian Assange announced Tuesday, promising more revelations based on the group's stash of confidential U.S. embassy cables and other leaks.

Assange, 39, spoke to reporters outside London's high-security Belmarsh Magistrates' Court, where he and his lawyers appeared for a hearing in his fight against extradition to Sweden, where he is wanted in a sex-crimes inquiry.

WikiLeaks sparked an international uproar with the publication of hundreds of classified U.S. diplomatic cables late last year, revelations that caused weeks worth of embarrassing news stories for the U.S. and its allies. But the flow of leaks, published in The New York Times, The Guardian, Der Spiegel, Le Monde and El Pais, has slowed recently amid a barrage of online attacks, financial difficulties and the Swedish prosecution of Assange.