A British court ruled Tuesday that Julian Assange can’t be extradited to the United States on espionage charges unless U.S. authorities guarantee he won’t get the death penalty, giving the WikiLeaks founder a partial victory in his long legal battle over the site’s publication of classified American documents.

Two High Court judges said they would grant Assange a new appeal unless U.S. authorities give further assurances within three weeks about what will happen to him. The ruling means the legal saga, which has dragged on for more than a decade, will continue — and Assange will remain inside London’s high-security Belmarsh Prison, where he has spent the last five years.

Judges Victoria Sharp and Jeremy Johnson said the U.S. must guarantee that Assange, who is Australian, “is afforded the same First Amendment protections as a United States citizen, and that the death penalty is not imposed.”

The judges said that if the U.S. files new assurances, “we will give the parties an opportunity to make further submissions before we make a final decision on the application for leave to appeal.” The judges said a hearing will be held May 20 if the U.S. makes those submissions.

The U.S. Justice Department declined to comment Tuesday.

Assange’s supporters say he is a journalist protected by the First Amendment who exposed U.S. military wrongdoing in Iraq and Afghanistan that was in the public interest.