LONDON — WikiLeaks founder Julian Assange on Thursday began what is likely to be a long, high-profile and politicized legal battle against extradition to the United States, telling a packed British courtroom that he would not willingly surrender to U.S. authorities.

Assange, 47, has been under investigation in the United States for his role in the release of classified military and diplomatic documents in 2010, and an indictment unsealed in April charged him with conspiring with U.S. Army intelligence analyst Chelsea Manning to hack into a Defense Department computer.

Asked at the beginning of Thursday’s hearing at Westminster Magistrates’ Court whether he wanted to consent to being extradited to the United States, Assange said he did not.

“I do not want to surrender for extradition for doing journalism that has protected many people and won many awards,” said Assange, who was wearing a black jacket and jeans and speaking via video link from a recording room at Belmarsh Prison.

Representing the U.S. government in court, British lawyer Ben Brandon said Assange stands accused of abetting the “largest compromise of classified information in U.S. history.”

Assange would face a maximum of five years in prison if convicted.

The hearing lasted about 15 minutes before it was adjourned until May 30. A more substantive hearing was set for June 12.

Signaling that this was just the start of a lengthy legal process, District Judge Michael Snow said that a “full extradition hearing is still many months away.”

It was Assange’s second court appearance in as many days. On Wednesday, he was sentenced to 50 weeks in prison for jumping bail in 2012. At the time, he was seeking extradition to Sweden, where he was wanted for questioning over sexual assault allegations. The judge in the case rebuked Assange for avoiding justice and insulting the British judiciary by seeking refuge in the Embassy of Ecuador in London.

Swedish prosecutors are considering whether to reopen their investigation into a rape claim against Assange, which he denies. If both Sweden and the United States attempt to extradite Assange, it would be up to British officials to decide which request, if any, to honor first.

Legal experts say the extradition process could take years as it weaves through various courts.