WASHINGTON -- Attorneys for the father of a cleric trying to inspire Muslims to kill Americans argued in court Monday to keep his son from being targeted for death by President Obama.

U.S. District Judge John Bates heard arguments in the case of Anwar al-Awlaki on the same day that the American cleric made a renewed call for jihad against U.S. citizens in a video posted on extremist websites.

Al-Awlaki, believed to be hiding in Yemen, was linked to last year's shooting at Fort Hood, Texas, and the attempted bombing of a U.S.-bound flight last Christmas. In the latest video, he said all Americans are the enemy and Muslims should kill any of them at will without consulting anyone.

Al-Awlaki's father, Nasser al-Awlaki of Yemen, said in a lawsuit that international law and the Constitution prevent the Obama administration from unilaterally targeting his son for death unless he presents a specific imminent threat to life or physical safety and there are no other means to stop him. The suit also seeks to force the government to disclose standards for determining whether U.S. citizens like his son, born in New Mexico, can be targeted for death.

"What the government is doing is imposing the death penalty without trial," said Jameel Jaffer, a lawyer for the American Civil Liberties Union, which along with the Center for Constitutional Rights has taken al-Awlaki's case.

Administration officials have confirmed to The Associated Press that al-Awlaki is on a capture or kill list, although Justice Department attorney Douglas Letter said in court that he would neither confirm nor deny it. But Letter said if al-Awlaki turns himself over to authorities, he's in no danger of the United States using lethal force against him.

Letter told Bates the court has no legal authority to be "looking over the shoulder" of the president as he makes military decisions to protect Americans against terrorist attacks.

"We're going to the very core powers of the president as commander in chief," Letter said.

Bates, an appointee of President George W. Bush, challenged both sides on their arguments, which were moved to the largest hearing room at the courthouse to accommodate the hundreds of people who turned out to listen.

For instance, Bates questioned the Justice Department on why the courts have authority to approve surveillance of Americans overseas but not their killing. And he pressed al-Awlaki's attorneys on why they think the cleric would want his father to take up the case when he has denounced the authority of the U.S. judicial system.

Jaffer said the father and son are not in contact because of the threat of death against the son. But he said the prospect that Anwar al-Awlaki could face indefinite detention without charge is enough to keep him from taking up the case himself, so his father is trying to act in his best interest.

Jaffer acknowledged that Anwar al-Awlaki said some "nasty" things about the United States and said he is not suggesting that Obama is acting in bad faith. But he said putting al-Awlaki on the targeted kill list without review would give the president carte blanche to assassinate any American accused of being involved in terrorism.