Funerals were held across the United States on Saturday for several victims of the Fort Hood killings, as President Barack Obama urged Congress to avoid politicizing the tragedy.

Thirteen people died in the Nov. 5 shooting rampage at a military base in Fort Hood, Texas.

During one ceremony in Plymouth, Ind.,, mourner Sheila Ellabarger watched the funeral procession for Army Staff Sgt. Justin DeCrow. She told The Associated Press that her children had gone to the same school as the soldier.

"He was killed by a terrorist in my mind but he was still killed in the line of duty," she said. "We owe him a debt of gratitude, him and his family and the other soldiers. We owe them our lives, our freedom."

Hundreds of kilometres away, a service took place in a high school gymnasium in Kiel, Wis., for Staff Sgt. Amy Krueger.

The 29-year-old had joined the military after the 2001 terrorist attacks, and was ready to deploy to Afghanistan for a second time before her death.

"Her smile would light up any room, her energy would envelope all of those around her," her parents, Jeri Krueger and David Diem, said in a statement. "It is that smile and that energy that keeps us going throughout this difficult time."

The two soldiers were among roughly half a dozen people mourned on Saturday.

Meanwhile, in a weekly video address, Obama said the government must investigate and address any flaws in the system that could lead to a similar tragedy.

"All of us should resist the temptation to turn this tragic event into the political theatre that sometimes dominates the discussion here in Washington," he said.

"The stakes are far too high."

"We must compile every piece of information that was known about the gunman. Once we have those facts, we must act upon them."

Along with the 13 deaths, 29 people were wounded on the Fort Hood military base.

Maj. Nidal Malik Hasan, a 39-year-old Army psychiatrist, is charged with 13 counts of murder.

An officer who responded to the scene shot Hasan. His lawyer says he may be paralyzed from the waist down.

Obama has already ordered a review of intelligence on Hasan and an investigation into whether authorities properly followed up on what they knew.

Michigan Rep. Peter Hoekstra, who is on Congress' Intelligence Committee, revealed this week that terrorism investigators overseen by the FBI knew Hasan had sent emails to a radical Muslim cleric in Yemen who encouraged Muslims to kill American soldiers in Iraq.

Hasan either received or made wire transfers to Pakistan, and Texas congressman Michael McCaul, who is on the Homeland Security Intelligence Committee has alleged the transactions may be part of terrorist financing.

The questions over Hasan's alleged financial dealings in Pakistan are underscored by reports that he lived frugally despite a high salary.

Hasan's financial file has been sealed until the investigation is closed, but he likely earned US$92,000 a year, with about $36,000 in possible bonuses. Despite that, he rented a modest apartment, which cost only $350 per month and drove a 2006 Honda.

With files from The Associated Press