WASHINGTON — Intelligence agencies intercepted communications last year and this year between Maj. Nidal Malik Hasan, who is accused of killing 13 people at Fort Hood, and a radical cleric in Yemen known for incendiary anti-American teachings. But federal authorities dropped an inquiry into the matter after deciding that the messages warranted no further action, government officials said Monday.

Hasan's exchanges with the imam, Anwar al-Awlaki, once a spiritual leader at a mosque in suburban Virginia where Hasan worshipped, included 10 to 20 e-mails from Hasan to the imam, said Rep. Peter Hoekstra of Michigan, the ranking Republican on the House Intelligence Committee. Awlaki responded to Hasan at least twice, Hoekstra said, but he described the responses as "innocent."

It is not clear what was said in the exchanges and whether they would have offered a hint of the major's outspoken views or his increasingly troubled emotional state.

The communications, which were the subject of an inquiry by the FBI and Army investigators, provide the first indication that Hasan, 39, an Army psychiatrist, was in direct communication with the cleric, who on Monday praised the major on his Web site, saying he "did the right thing."

Federal officials briefed on the case said they were convinced that their decision to break off the investigation was reasonable based on the information about Hasan that was compiled at the time, which they said gave no indication that he was likely to engage in violence.

Asked whether the shootings constituted terrorism and whether any ties exist between Hasan and al Qaeda, White House spokesman Robert Gibbs said the Defense Department and the FBI are jointly leading an investigation. "The president has been very clear with everyone that no stone should be left unturned to figure out how and why this happened, and to ensure that it never happens again," he said.

Investigation officials said Monday that Hasan would be charged in military court.

Federal officials with knowledge of the communications between Hasan and Awlaki said those exchanges did not alter the prevailing theory that Hasan acted by himself, lashing out as a result of a combination of factors, among them his outspoken opposition to American policy in Iraq and Afghanistan and his deepening religious fervor as a Muslim.

But Hoekstra said, "For me, the number of times that this guy tried to reach out to the imam was significant."

And U.S. Rep. Michael McCaul of Austin said Monday that he stood by his initial characterization of the shootings as an act of terror.

"I believe there was a rush to judgment that Mr. Hasan was acting on his own," said McCaul, the highest-ranking Republican on the House Subcommittee on Intelligence, Information Sharing and Terrorism Risk Assessment. He called it imperative that the military and FBI search for outside influences, such as al Qaeda. He said he's also asked for subcommittee hearings on the matter.

"He was operating alone" at Fort Hood, McCaul said. "The question remains whether he was coordinating with terrorist organizations on the outside."

McCaul was responding to questions submitted in a Web chat at statesman.com.

"The fact he reportedly stated 'Allahu Akbar,' which means 'God is great,' is insightful as to his intent and motivation as this is common Jihadist terminology," McCaul said.

Suicide bombers in the Middle East are often reported to utter the Arabic phrase before detonating their explosives.

"We've known for years that al Qaeda has been targeting U.S. military installations. The Fort Dix plot was an example of this. It is their playbook, and they return to their playbook," McCaul said.

He was referring to a foiled plot against that New Jersey installation involving five men convicted last year of conspiring to kill U.S. military personnel in 2006 and 2007. Prosecutors said the men were inspired by Osama bin Laden, though they weren't accused of having ties to foreign terror groups.

McCaul said the U.S. military must screen individuals more thoroughly to protect against "infiltration." The FBI and military officials have searched Hasan's apartment in Killeen, and the contents of his seized computer are being examined for signs of affiliations with terrorist groups, officials said.

Hasan, who was shot four times Thursday, is conscious and talking to medical personnel at Brooke Army Medical Center in San Antonio, hospital officials said.

Awlaki said Monday on his English-language Web site that Hasan is "a hero."

"He is a man of conscience who could not bear living the contradiction of being a Muslim and serving in an army that is fighting against his own people," the cleric said. He praised "the virtue" of the Fort Hood shootings and said the only way a Muslim could justify serving in the U.S. Army was if he intended to "follow in the footsteps of men like Nidal."

Awlaki, an American citizen born in New Mexico to Yemeni parents, preached at the Dar Al Hijrah Islamic Center in Falls Church, Va., when Hasan attended in 2001.

U.S. authorities say Awlaki, who left the United States in 2002 and later settled in Yemen, has become a supporter and leading promoter of al Qaeda.

His exact whereabouts have been unknown since he was released from a Yemeni jail last year. He is on Yemen's most wanted militant list, according to three Yemeni security officials.

The officials said Awlaki was arrested in 2006 with a small group of suspected al Qaeda militants. They said he was released more than a year later after signing a pledge not to break the law or leave the country.