Syrian Democratic Forces hold a position on the eastern frontline of Raqa on September 24, 2017, as they battle with the support of US special forces to clear the last remaining Islamic State group jihadists holed up in their crumbling stronghold of Raqa. BULENT KILIC/Getty Images

The United States military denied legal representation to a U.S. citizen, who was detained in September for allegedly fighting for the Islamic State group.

The man, who was detained as an “enemy combatant” and whose identity remains a secret, has neither been charged nor allowed to meet lawyers, Huffington Post reported.

The Defense Department admitted Thursday the man was denied an attorney even though he requested for one.

The revelation came after the American Civil Liberties Union Foundation (ACLU) filed a petition for habeas corpus Oct. 5, in which the group argued the man should be allowed to have access to lawyers.

“It is indisputable that a U.S. citizen has the right to access the courts, but the government has made that right basically impossible to exercise,” ACLU lawyer Jonathan Hafetz, who argued the case Thursday, said in Washington.

Without access to the courts, Hafetz continued, “all the rights in the Constitution are basically null and void,” according to the Huffington Post report. Each day “is an assault on his rights and on the Constitution.”

The ACLU suit also quoted the Supreme Court ruling after Sept. 11, 2001 attacks, which said U.S. citizens cannot be detained indefinitely as “members of al Qaeda or other terrorist groups.” The court also ruled they are entitled to an attorney and also the right to challenge the proof against them.

But the Trump administration argued in court filings that the prisoner is being held under “law of war” and does not have right to a lawyer. The filings added ACLU cannot act on the man’s behalf as they had never met him.

When District Judge Tanya Chutkan asked for a response from the Justice Department, they revealed the FBI interrogators had informed the citizen of his right to an attorney. The man requested for one, they just didn’t provide one, the Daily Beast reported.

“The individual stated he understood his rights, and said he was willing to talk to the agents but also stated that since he was in a new phase, he felt he should have an attorney present. The agents explained that due to his current situation, it was unknown when he would be able to have an attorney, and the individual stated that it was ok and that he is a patient man,” the Justice Department wrote in its latest court filing.

Read the full response of the Justice Department here.

Judge Chutkan responded to the claims, saying it was “frightening” that the government offered no estimate of how long it could legally detain the U.S. citizen, according to the Daily Beast.

The alleged IS group fighter had reportedly surrendered Sept. 12 to a Syrian rebel militia, which turned him over to the U.S. military, New York Times reported.

The case led to a dilemma in the Trump administration as to how to detain the man, as the evidence against him was not enough.

A senior administration official, who chose to remain anonymous, said the man was born in America, thus making him a citizen. But his parents were “visiting foreigners” and he grew up in the Middle East, according to the New York Times.