Nidal Malik Hasan, the suspect in last week's mass shooting incident at Fort Hood army base, Tex., is now conscious and began to talk, U.S. authorities said on Monday.

Hasan, a 39-year-old licensed U.S. Army psychiatrist who worked at a hospital in the base, was shot several times by police after his shooting rampage left 13 dead and 30 others wounded at the Soldier Readiness Center in the base on Nov. 5.

He is in critical but stable condition and is under intensive care at Brooke Army Medical Center in San Antonio, Tex., according to hospital spokesman Dewey Mitchell.

Hasan's ventilator was removed over the weekend, and he began talking afterward, Mitchell told reporters.

The suspect is now speaking with hospital staff, but Mitchell was unable to say whether Hasan has been speaking with Army investigators. His motivation in the case hasn't been identified.

The development comes a day after Army investigators asked troops and civilians for help gathering clues about the shooting, saying those who fled the gunfire might have evidence.

As of Sunday, 16 gunshot victims remained hospitalized, plus Hasan, Fort Hood spokesman John Rossi told reporters.

Efforts to assist those affected by the incident, including family members of soldiers at the post, were ongoing, he said.

U.S. Army Criminal Investigation Command spokesman Chris Grey said on Saturday all evidence indicates that Hasan acted alone and there was no indication of "friendly fire."

The suspect's brother, Eyad Hasan, released a statement on Saturday saying the family was in a "state of shock and disbelief over this dreadful news."

He said the family has faith in the legal system.

An earlier statement from another family member said Hasan, a U. S. citizen of Palestinian descent, had been telling his family that he wanted to get out of the military but had been unsuccessful in doing so.

Other reports said Hasan was upset about his pending deployment to Afghanistan, which had been scheduled for late November.

U.S. President Barack Obama and First Lady Michelle Obama will attend a Tuesday memorial service for the victims at Fort Hood, according to the White House.