The two-page memo, first reported by AP, was submitted in an immigration court filing and published by Khalil’s legal team. It does not allege any criminal conduct by Khalil, who was born in Syria but is of Palestinian descent, and a legal permanent resident in the US. But Rubio wrote that he could be expelled from the US for his beliefs.

   Khalil was a negotiator with the Columbia administration during the pro-Palestine student protest campus movement last year. Rubio said that while the activist’s activities were “otherwise lawful”, letting him remain in the country would undermine “US policy to combat anti-Semitism around the world and in the United States, in addition to efforts to protect Jewish students from harassment and violence in the United States».

   “Condoning anti-Semitic conduct and disruptive protests in the United States would severely undermine that significant foreign policy objective,» he wrote in the undated memo.

   Rubio has relied on a statute from the Immigration and Nationality Act of 1952 that gives the Secretary of State the authority to personally order deportations of those whose presence would have adverse foreign policy consequences for the US.

   The submission was filed after Judge Jamee Comans ordered the government to produce its evidence against Khalil before a hearing on Friday on whether it can continue detaining him during immigration proceedings. The activist was detained at his residence in New York by plainclothes immigration officers as his wife, an American citizen who was eight months pregnant, watched on.

   Khalil’s lawyer was told by the officers that his green card had been revoked. He was moved to an immigration detention centre in Louisiana and the government has started deportation proceedings against him.

   The US administration, including President Donald Trump, has accused Khalil of disseminating Hamas propaganda. Trump has described him as a «radical pro-Hamas student». Khalil has roundly rejected these accusations.

   After his detention, the Department of Homeland Security charged him for civil offences, including withholding information on his green card application, such as his working with a United Nations relief agency and his involvement with a pro-Palestine activist group at Columbia.

   In a letter sent from jail last month, he called himself a «political prisoner» and said the Trump administration was “targeting me as part of a broader strategy to suppress dissent».

   Khalil is one of several current and former students and academics in the US who have been detained or deported after speaking out against the Gaza war. In January, Trump signed an executive order that called for the revocation of visas of foreign students and others who took part in pro-Palestinian protests on university campuses.

   News of the memo comes a day after the Department of Homeland Security announced that social media activity perceived as anti-Semitic, as well as the «physical harassment of Jewish» people, would be grounds to deny applicants US visas and permanent residency.