Mahmoud Khalil will appeal his deportation case to the US Supreme Court after a federal appeals court declined to rehear his challenge to immigration detention.

The ruling came in a narrow 6-5 decision on Friday, according to Khalil’s legal team.

Khalil, a US permanent resident, has been targeted for deportation by the US President Donald Trump’s administration over his pro-Palestine activism.

His lawyers have argued that his detention violated free speech protections.

Last June, a federal judge ordered Khalil’s release and blocked deportation proceedings, but an appeals court later ruled that the lower court lacked jurisdiction.

“Today’s decision is not the final word, and we still strongly believe in our arguments going forward,” Brett Max Kaufman said in a statement.

“Federal courts must have the power to step in when the government exploits our country’s immigration system to punish people for their constitutionally protected speech”, he added.

Separately, Khalil’s lawyers are also challenging a final deportation order issued by the Board of Immigration Appeals.

The Trump administration has accused Khalil of posing a national security concern and of omitting past work for the UN agency for Palestinian refugees, UNRWA, from immigration paperwork. 

Khalil denies wrongdoing and has not been charged with any crime.