Soon after Pentagon officials named the gunman at the Fort Hood facility as Nidal Malik Hasan, Islamic groups rallied to condemn an act President Barack Obama had earlier described as a "horrific outburst of violence".
"The guy's name is a Muslim name," Ibrahim Hooper of the Council on American-Islamic Relations (CAIR) told AFP, expressing fears about damage to inter-faith relations, already strained by the attacks of September 11, 2001 and wars in Iraq and Afghanistan.
In a statement, CAIR condemned the shootings as a "cowardly attack" adding that "no political or religious ideology could ever justify or excuse such wanton and indiscriminate violence.
"American Muslims stand with our fellow citizens in offering both prayers for the victims and sincere condolences to the families of those killed or injured."
Qaseem Ali Uqdah, who was a Marine for 21-years before becoming the executive director at the American Muslim Armed Forces and Veterans Affairs Council, now fears a "witch-hunt" such as that which followed September 11.
"This is a criminal act and we have to treat it like a criminal act, not something to do with religion" he said.
For the estimated 3500 Muslims in the US armed forces, Uqdah said there could be some fallout from the attack.
"What we don't need is people down range sitting in foxholes [in Afghanistan or Iraq] questioning if you are a Christian, if you are a Muslim or if you are a Jew ... that is not what we need as a nation.
"We need to fight the war on terror together," he added.
In a Pew survey published last September, 38 per cent of respondents said that Islam encouraged violence more than other religions.
Fifty-eight per cent said there was a lot of discrimination against Muslims in the United States.