Earlier in the day, UK authorities on behalf of the United States arrested Assange inside the Ecuadorian Embassy in London while US authorities unsealed an indictment charging the WikiLeaks founder with computer intrusion conspiracy, which carries a maximum sentence of five years in prison.
"The fact that this indictment has existed for over a year underscores… that compelling Chelsea to testify would have been duplicative of evidence already in the possession of the grand jury, and was not needed in order for US Attorneys to obtain an indictment of Mr. Assange," Manning’s lawyers said on Thursday.
Manning has been in detention since 8 March after she refused to appear before a grand jury to testify about her release of classified material to WikiLeaks in 2010.
"Since her testimony can no longer contribute to a grand jury investigation, Chelsea’s ongoing detention can no longer be seriously alleged to constitute an attempt to coerce her testimony," the lawyers added.
Ecuadoran President Lenin Moreno said he lifted Assange’s asylum status after assurances from UK authorities that the whistleblower would not be extradited to a country where he would face torture or the death penalty.
Assange gained fame after WikiLeaks published a large number of leaked files, including some referring to US military operations in Afghanistan and Iraq, and conditions in the Guantanamo detention camp.
Since 2012, Assange had been residing in the Ecuadorian Embassy in London to avoid extradition to Sweden, where he faced a probe over allegations of sexual offenses.
Assange denied those allegations and called them politically motivated. While the Swedish police dropped the investigation in 2017, Assange was still wary of being extradited to the United States.