Outgoing Mexican President Andres Manuel Lopez Obrador hailed the release of the WikiLeaks founder Julian Assange from Belmarsh prison while speaking in Mexico City on Tuesday.

"I congratulate Julian, his family, his father, his brothers, his friends, and the millions of Mexicans and all the countries in the world who participated in making Julian Assange's freedom possible. We also joined that campaign and as I expressed on my Facebook, we are very happy about Julian's release from prison," said the politician.

Obrador also compared Assange's incarceration with 'freedom in prison.'

"It was a very unfair thing, it was like having freedom, and especially freedom of expression, in prison," highlighted the politician.

Outgoing Mexican president also admitted that the country's government was working with former and acting US administrations to help resolve Assange's case.

"We are very happy, they [Assange's family] know what we did both with the government of President Trump and with the government of President Biden. We are very content," concluded Obrador.

The WikiLeaks founder left Belmarsh on Monday evening after reaching the plea deal, boarding a plane at London's Stansted Airport.

The hearing's location in Saipan - the largest of the Northern Mariana Islands, a US commonwealth - was reportedly due to its proximity to Australia and his own opposition to travelling to the United States.

He had been detained in the London prison since 2019, and fought a long-running extradition battle with the US over 18 charges related to the release of classified documents involving the Iraq and Afghanistan wars.

He was initially granted political asylum by Ecuador in the British capital in 2012 but was dragged from the embassy by UK police seven years later.