More than 70 MPs and peers - mostly from the opposition Labour Party - wrote to Home Secretary Sajid Javid calling for the 47-year-old whistleblower to be extradited to Sweden if Swedish prosecutors reopen a rape inquiry against him.
Within hours of police hauling him out of the embassy on Thursday, the 47-year-old Australian appeared in court for breaching his British bail conditions in 2012 and to face a subsequent United States extradition request.
The MPs note that the investigation in Sweden was "discontinued only because of Assange's unavailability" while he was inside the Ecuadorian embassy in London.
But on Friday, Swedish prosecutors said they were examining the rape case at the request of the alleged victim's lawyer.
Diane Abbott, Labour's spokeswoman for domestic affairs, said the government should block the extradition on human rights grounds. British police said Assange had been arrested Thursday for breaching his bail conditions and in relation to the USA arrest request.
WikiLeaks says he will fight the US extradition request and has been meeting with his legal team to plan his defence.
He was retweeted by Pamela Anderson - one of Assange's most famous supporters - who has previously described Mr Corbyn as "clearly a decent and fair man".
"We are going to do everything we possibly can to get the Swedish police investigation re-opened so that Assange can be extradited to Sweden and prosecuted for rape", lawyer Elisabeth Massi Fritz tweeted.
"Regardless of where you stand on this, he must face these allegations in Sweden and clear his name if he thinks he's innocent", Maajid said.
Britain is bound by law not to extradite a suspect to a country where he or she could face execution for the crime, but this is not an issue at the moment because the crime Assange faces does not put him at risk of capital punishment, he said.
However, relations with his Ecuadoran hosts gradually soured and pro-US President Lenin Moreno on Thursday pulled his asylum, cancelled his citizenship and permitted British police to remove Assange.
"Though the Secretary of State does have very limited powers to interfere, I don't see that discretion being used", she said.
The US official said that within the 60-day period, US authorities could modify or add to the current charges they have filed against Assange.
The extradition process is not swift, and Assange could appeal several times if decisions go against him.
Assange has always denied the allegations, which he feared would lead to him being extradited to the United States and facing trial over the leak of hundreds of thousands of secret USA military and diplomatic documents in 2010, which brought WikiLeaks to prominence.