Democratic lawmakers are calling on President Donald Trump to dismiss an aide accused of being a member of a Hungarian far-right nationalist group.

Reps. Eliot Engel and Nita Lowey, both from New York and Jewish, are sending a letter to Trump urging him to fire Sebastian Gorka, Politico reported Friday. At least 18 House of Representatives members, all Democrats, have signed the letter, according to Politico.

“As members of the US Congress who care deeply about fighting anti-Semitism at home and abroad, we urge you to immediately dismiss senior White House counterterrorism adviser Sebastian Gorka. Based on recent revelations about Mr. Gorka’s public support for and membership in several anti-Semitic and racist groups in Hungary, he is clearly unfit to serve in any position of responsibility in the White House,” the letter said, citing Gorka’s alleged ties to various far-right groups in Hungary.

Earlier this month, the Forward published a 2007 recording in which Gorka said he was not opposed to the establishment of the Hungarian Guard, a nationalist militia that later was accused of racism and anti-Semitism. In 2009, a Hungarian court banned the Guard.

According to an article published last month by the Forward, Gorka, a native of Britain who is the son of Hungarian immigrants, allegedly is a member of Historical Vitézi Rend. The group is a namesake of Vitézi Rend, a defunct order of merit that had existed as a state entity for 20 years until 1944 under the rule of Miklos Horthy, Hungary’s Nazi-allied leader. Vitézi Rend was disbanded, outlawed and ceased to exist in the 1940s following the World War II defeat of Nazi Germany.

Gorka has denied being a fascist or anti-Semite. In a statement published last month by Tablet, Gorka was quoted as writing, “I have never been a member of the Vitez Rend. I have never taken an oath of loyalty to the Vitez Rend.” The statement did not mention the Historical Vitézi Rend group.

The letter by Engel and Lowey referred to the recording as well as reports of Gorka’s ties to the Vitezi Rend.

Others who signed the letter include Reps. Brad Schneider of Illinois, Jerrod Nadler of New York and Debbie Wasserman Schultz of Florida.

In March, Nadler and three top Democratic senators voiced concern over reports of Gorka’s alleged membership in the Historical Vitezi Rand.

Nadler sent a letter to Trump, and Sens. Dick Durbin, D-Ill., Ben Cardin, D-Md., and Richard Blumenthal, D-Conn., sent one to the acting deputy attorney general, Dana Boente, and Homeland Security Secretary John Kelly, urging them to investigate the circumstances of Gorka’s path to US citizenship, and whether he concealed his alleged membership in the group as part of his naturalization process.

On Thursday, The Jerusalem Post announced that Gorka would be speaking at its annual conference on May 7 in New York.