WASHINGTON (Reuters) - The Obama administration on Saturday urged a federal judge to reject a challenge to a program that targets for killing U.S. citizens like Muslim cleric Anwar al-Awlaki who have joined militant groups and have been tied to terrorism plots.

The Obama administration earlier this year authorized the Central Intelligence Agency to capture or kill al-Awlaki, who is believed to be in hiding in Yemen where al Qaeda militants have been operating for years, U.S. officials have said.

Obama administration officials have also said Americans who travel overseas to fight alongside groups like al Qaeda -- blamed for the September 11, 2001 attacks in New York, Washington and Pennsylvania -- are legitimate targets for lethal strikes.

The cleric’s father, Nasser al-Awlaki, sued, saying targeted killings were illegal under the U.S. Constitution because Americans should be prosecuted in a court and should only be targeted for lethal force if there was an imminent threat and no other way to stop it.

With the help of the American Civil Liberties Union and Center for Constitutional Rights, he asked a federal judge to issue an injunction and force the administration to publicly reveal its criteria for determining who can be targeted.

The Justice Department, while refusing to confirm that the targeted kill program existed, said in a court filing that the father has no legal standing to sue and that U.S. courts should not interfere with how the government protects the country.

“The lawsuit, which never denies that Anwar al-Awlaki is an active leader of Al Qaeda in the Arabian Peninsula, asks a court to take the unprecedented step of intervening in military matters and directing the president how to manage military action -- all for the benefit of a leader of a foreign terrorist organization,” said Justice Department spokesman Matthew Miller.

“If Anwar al-Awlaki wishes to access our legal system, he should surrender to authorities and be held accountable for his actions,” he said. The cleric has said he has no intention of surrendering to U.S. authorities.

With Internet postings on the Internet by al-Awlaki promoting and praising attacks against the United States, he has become a major focus by U.S. intelligence and law enforcement agencies.

U.S. investigators have found that he communicated with the Army major who went on a shooting spree last year at Fort Hood, Texas killing 13 people and that he instructed the Nigerian man who tried to blow up a U.S. airliner on Christmas Day.

In response to the growing activities of al Qaeda in the Arabian Peninsula group, the Obama administration has ramped up foreign aid and assistance to Yemen, which has struggled against militant groups for years.

The administration, which often stresses its bid to be more transparent, also invoked the argument that the case should be dismissed because it involved state secrets and revealing them would compromise national security.

“It strains credulity to argue that our laws require the government to disclose to an active, operational terrorist any information about how, when and where we fight terrorism,” Miller said.

Al-Awlaki was born in New Mexico and lived in Virginia until late 2001. No charges have been publicly filed against the cleric, who has dual U.S. and Yemeni citizenship.

“The idea that courts should have no role whatsoever in determining the criteria by which the executive branch can kill its own citizens is unacceptable in a democracy,” the ACLU and CCR organizations said in a statement. “In matters of life and death, no executive should have a blank check.”

A court hearing is set for October 22 to consider the case.