LONDON — Julian Assange, the founder of WikiLeaks, appeared in a British court on Thursday for an initial hearing on whether he will be extradited to the United States to face prosecution in connection with one of the most serious leaks of classified material in American history.

Mr. Assange, 47, made a brief appearance by video link in Westminster Magistrates Court in London from Belmarsh Prison in another part of the city. A day earlier, he had been sentenced to 50 weeks in prison for bail-jumping.

The hearing on Thursday lasted just a few minutes, in which Mr. Assange told the judge that he did not wish to surrender himself to be prosecuted in the United States for what he called “journalism that has won many awards,” according to The Associated Press. His next hearing, in what promises to be a long extradition fight, is scheduled for May 30.

The American indictment against him stems from a leak in 2010 of hundreds of thousands of classified documents, mostly related to the wars in Iraq and Afghanistan, that proved damaging and embarrassing for the United States and its allies. Mr. Assange faces a charge of conspiring with the former Army intelligence analyst Chelsea Manning to hack into a Pentagon computer network, a crime punishable by up to five years in an American prison.