U.S. Army officials said Friday that they are reviewing protection measures following Thursday's shooting rampage at Fort Hood, Texas, as the 13 victims were remembered.

Flags flied half staff across the nation on the orders of President Barack Obama.

Meanwhile, military bases all over the world observed a moment of silence at 2:34 p.m., which marked 24 hours since the shooting that killed 13 and wounded 30 started.

Obama extended his sympathies to the families of the victims and urged Americans not to jump to conclusions while law enforcement officials gather facts about the shootings.

"There are family, friends, and an entire nation grieving right now for the valiant men and women who came under attack yesterday in one of the worst mass shootings ever to take place on an American military base,” Obama said. “So from now until Veterans Day, I have ordered the flags be flown at half staff at the White House and other federal buildings. This is a modest tribute to those who lost their lives even as many were preparing to risk their lives to their country."

"This is a time for the Army family to stand together. This is a time for 'Army strong' to mean what it says," said U.S. Secretary of the Army John McHugh. "And this is a time to know that we are working to make sure that their safety and security is met to the highest degree."

The White House says the president plans to attend the memorial service for the victims, which will be scheduled at the convenience of their families.

Earlier Friday, the family of the accused shooter, Army psychiatrist Nidal Malik Hasan, released a statement calling his alleged actions "despicable and deplorable.''

A spokeswoman for the family says they are cooperating with the investigation.

Officials try to determine what drove Hasan, 39, to unleash the attack.

Officials say Hasan opened fire at a medical processing center for soldiers returning from overseas, or about to be deployed.

As of late Friday, Hasan was on a ventilator and under heavy guard at an Army medical center in San Antonio, Texas, and was expected to survive.

Medical officials say many of the 30 wounded in the shooting are still in danger of losing their lives.

Hasan was set to be deployed to Afghanistan to counsel soldiers suffering from combat stress.

Investigators have searched his apartment and seized his computer, but have not released any other details.

A candlelight vigil for the shooting victims was held at Fort Hood on Friday evening.