Democrats have vowed to vote against the proposal after a faction of senators broke with party to pass a compromise

More than 252 Venezuelans expelled to El Salvador under Donald Trump’s mass deportation policy suffered systematic and prolonged torture and abuse, including sexual assault, during their detention, according to a report published on Wednesday.

The report, compiled jointly by Human Rights Watch (HRW) and Cristosal – a group investigating violations in Central America – says conditions at El Salvador’s sprawling “terrorist continent center” (Cecot) breached the UN’s standard minimal rules for the treatment of prisoners. It cites “inhumane prison conditions, including prolonged incommunicado detention, inadequate food” and other shortcomings.

The groups accuse the Trump administration of willful complicity in the suffering deportees endured after being flown to El Salvador in March and April, insisting that it ordered the men’s deportation while fully aware that they would be mistreated or even face threats to their lives.

They are calling an “independent investigation” by the US justice department, although they admit the prospect is unlikely. They are also demanding the Trump administration stop deporting third-country nationals to El Salvador.