(CNN)WikiLeaks founder Julian Assange has been "arbitrarily detained" by the governments of Sweden and the United Kingdom since 2010, a U.N. panel ruled on Friday.

Melinda Taylor, Assange's lawyer, called the ruling "a resounding vindication of Mr. Assange's position."

But the judgment by the U.N. working group is a "moral recommendation" -- it's not legally binding, so authorities don't have to abide by it.

Assange has been holed up in the Ecuadorian Embassy in London for the past three and a half years, afraid that if he leaves, he'll end up facing the death penalty in the United States.

Here's why.

Assange is currently wanted in Sweden on rape allegations.

He was arrested in the UK in 2010 and has been dealing with the legal process since.

That culminated with a losing appeal before the UK's Supreme Court, after which he fled to the Ecuadorian Embassy in London (the country has granted him political asylum.)

Since there is still a European Arrest Warrant for him still in place, according to the UK Foreign and Commonwealth Office, his options are to stay inside the embassy or leave and face arrest and get put on a plane to Sweden.

Assange said if he ends up back in Sweden he fears the country will extradite him to the United States, where he could face the death penalty for revealing government secrets.

Though he's not in the custody of Sweden or the UK, the United Nations Working Group on Arbitrary Detention says by putting Assange in this precarious situation, the two countries are depriving him of his liberty and freedom of movement.Not so fast, Sweden and the UK say.

Both countries released statements shortly after the U.N. announcement condemning the ruling.

"Mr. Assange has chosen, voluntarily, to stay at the Ecuadorian Embassy and Swedish authorities have no control over his decision to stay there," the Swedish government said in a press release. "Mr. Assange is free to leave the Embassy at any point. Thus, he is not being deprived of his liberty there due to any decision or action taken by the Swedish authorities."

Assange had said in advance of the panel's announcement Friday that, if the panel found against him, he'd walk out of the embassy and "accept arrest."

"However, should I prevail and the state parties be found to have acted unlawfully," Assange said, "I expect the immediate return of my passport and the termination of further attempts to arrest me."

But there is no assurance that will happen -- in fact, the UK Foreign and Commonwealth Office said on Friday that the U.N.'s recent ruling "changes nothing."

"We completely reject any claim that Julian Assange is a victim of arbitrary detention," it said in a press release. "An allegation of rape is still outstanding and a European Arrest Warrant in place, so the UK continues to have a legal obligation to extradite him to Sweden."