"We are a nation of laws and a jury has spoken," the first black U.S. president said in a statement. "I now ask every American to respect the call for calm reflection from two parents who lost their young son."
The jurors who deliberated for 16 hours over two days found Zimmerman not guilty of second-degree murder and manslaughter. All six women, who were sequestered for the three weeks of testimony, declined to speak to reporters and their identities were still sealed by the court.
In Sanford at the largely black Allen Chapel A.M.E. Church, pastor Valarie Houston dedicated a Sunday morning prayer service to Martin.
"I am hurt. I am sad. I am disappointed and my heart is overwhelmed with pains," Houston said. "I thought in my heart that justice would be served."
After the verdict, the focus seemed to be shifting to rallies and events in the upcoming days, and an examination of both Florida law, and whether the U.S. Department of Justuce should conduct a civil-rights investigation, according to the Orlando Sentinel.
The Sanford Pastors Connection group has announced it will hold a public community prayer service Monday afternoon at New Life Word Church to encourage peace and unity, a city spokeswoman said. Sanford Mayor Jeff Triplett, City Manager Norton Bonaparte and Police Chief Cecil Smith are scheduled to attend.
Another group has called for a statewide day of action in Florida for Trayvon. Dream Defenders said it would demonstrate outside the Capitol building and other locations Tuesday in response to the Zimmerman verdict and other civil-rights issues.
Case under review
Zimmerman, who showed little reaction when the decision was read, was unshackled from a monitoring device he had been wearing while on bail. He previously only left home in a disguise and body armor, his lawyer said.
His brother said he would remain out of public view for some time. Friends said the former neighborhood watch volunteer had recently spoken about the possibility of entering law school.
The tense drama that climaxed with the verdict had been building for more than a year, since police initially declined to arrest Zimmerman for shooting Martin, whose gray hooded sweatshirt has become a symbol of injustice for protesters.
The acquittal will weaken any wrongful death civil lawsuit that Martin's family might bring. Zimmerman's lead defense lawyer, Mark O'Mara, predicted Zimmerman would seek and win immunity from a civil suit.
A Justice Department spokesperson said in a statement on Sunday it would determine whether "the evidence reveals a prosecutable violation of any of the limited federal criminal civil rights statutes within our jurisdiction."
Reuters, Los Angeles Times and the Orlando Sentinel