(CBS/AP)-- A week after a Florida jury acquitted George Zimmerman in the death of 17-year-old Trayvon Martin, rallies were held across the country as activists pressed federal authorities to prosecute the former neighborhood watch volunteer on civil rights charges and pushed for changes to self-defense laws.
Zimmerman was found not guilty of both second-degree murder and manslaughter by a six-woman panel in last year's shooting death of Martin. His attorneys successfully argued that Zimmerman's use of force was justified as self-defense in the altercation with the unarmed teen.
The case has spurred a national debate about gun laws, the use of justifiable force and racial profiling, even prompting President Barack Obama to weigh in with personal remarks Friday on race relations in the U.S.
The "Justice for Trayvon" rallies were organized by the Rev. Al Sharpton's National Action Network and took place outside federal buildings in at least 100 cities, including New York, Miami and Los Angeles.
In New York, hundreds of people, including the music superstars Jay-Z and Beyonce, were assembled along with Sharpton and Sybrina Fulton, Martin's mother.
Fulton told the crowd she was determined to fight for societal and legal changes needed to ensure that black youths are no longer viewed with suspicion because of their skin color.
"I promise you I'm going to work for your children as well," she said to the rally crowd.
At a morning appearance at Sharpton's headquarters in Harlem, she implored people to understand that the tragedy involved more than Martin alone. "Today it was my son. Tomorrow it might be yours," she said.
Chants rang out across the rallies. "Justice! Justice! Justice! ... Now! Now! Now!" "We won't forget." "No justice! No peace!" Many also sang hymns, prayed and held hands.
And plenty of participants carried signs: "Who's next?" "I am Trayvon Martin." "Enough Is Enough."
"It's personal," said Cincinnati resident Chris Donegan, whose 11-year-old son wore a black hoodie to the rally, as Martin did when he died. "Anybody who is black with kids, Trayvon Martin became our son."
In addition to pushing the Justice Department to investigate civil rights charges against Zimmerman, Sharpton told supporters he wants to see a rollback of stand-your-ground self-defense laws.
"We are trying to change laws so that this never, ever happens again," Sharpton said.
Stand-your-ground laws are on the books in more than 20 states, and they go beyond many older, traditional self-defense statutes. In general, the laws eliminate a person's duty to retreat in the face of a serious physical threat.
Zimmerman relied on a traditional self-defense argument and didn't invoke stand-your-ground, though the judge included a provision about it in instructions allowing jurors to consider it as a legitimate offense. And race wasn't discussed in front of the jury. But the two topics have dominated public discourse about the case, and came up throughout Saturday's rallies.
Part of Sharpton's comments echoed those made by President Barack Obama on the case yesterday. "Racial profiling is not as bad as segregation, but you don't know the humiliation of being followed in a department store," Sharpton said.
In Indianapolis, the Rev. Jeffrey Johnson told about 200 attendees that the nationwide effort is about making life safer for young black men. Johnson said young black men still are endangered by racial profiling, and he compared Zimmerman's acquittal to that of four white officers in the beating of black motorist Rodney King in 1992.
"The verdict freed George Zimmerman, but it condemned America more," said Johnson, pastor of the Eastern Star Church in Indianapolis and a member of the board of directors of the National Action Network.
In Miami, Tracy Martin spoke about his son.
"This could be any one of our children," he said. "Our mission now is to make sure that this doesn't happen to your child."
He recalled how he vowed to Trayvon as he lay in his casket that he would seek justice.
"I will continue to fight for Trayvon until the day I die," he said.
Shantescia Hill held a sign in Miami that read: "Every person deserves a safe walk home." The 31-year-old mother, who is black, said, "I'm here because our children can't even walk on the streets without fearing for their lives."
At the New Orleans rally, La'Monte Johnson shared some of the same experiences.
The California native said he's been stopped multiple times by police and handcuffed "because I fit the description of someone they were looking for," though he noted charges were never filed against him.
"You can be the greatest black guy around, but you can't get away from it," he said. "You're not equal."
Last Saturday's verdict spurred protests throughout the week, leading to sporadic violence and some arrests - mostly in California - but there have been no widespread disturbances. Organizers hoped for a day of peaceful protest Saturday.
This week, Attorney General Eric Holder announced that the department would investigate whether Zimmerman could be charged under federal civil rights laws, which would require evidence that he harbored racial animosity against Martin. Most legal experts say that would be a difficult charge to bring.
Police in Sanford, Fla., say the Justice Department has placed a hold on all evidence related to case, including the gun Zimmerman used and which he would otherwise be legally entitled to reclaim.
Earlier this week, Fulton told "CBS This Morning" that she was "stunned" by the verdict.
"I thought surely that he would be found guilty of second degree murder, manslaughter at the least. But I just knew that they would see that this was a teenager just trying to get home. This was no burglar. This was somebody's son that was trying to get home."
Several of the jurors, who are still anonymous, have spoken out since delivering the verdict. In a CNN interview Monday, Juror B37, revealed that the jury was evenly split on a conviction in the initial vote. But she felt that both Zimmerman and Martin were equally responsible for the physical confrontation and that race played no factor.
The following day, four other jurors released a brief statement saying "the opinions of Juror B37, expressed on the Anderson Cooper show were her own, and not in any way representative of the jurors listed below."
The six-sentence statement - signed by Jurors B51, B76, E6 and E40 - did not specify what parts of the other juror's comments they disagreed with, but they did say that "serving on this jury has been a highly emotional and physically draining experience for each of us. The death of a teenager weighed heavily on our hearts but in the end we did what the law required us to do."
On Friday, in a surprise appearance in the White House briefing room, President Obama delivered extensive remarks about the case and about more broadly about the state of race in America.
"When Trayvon Martin was first shot, I said this could've been my son. Another way of saying that is, Trayvon Martin could have been me 35 years ago," he said.
"There are very few African-American men in this country who haven't had the experience of being followed when they were shopping at a department store, and that includes me," he said. He spoke about hearing the locks click on car doors while crossing the street -- something Mr. Obama said he experienced before he was senator -- or seeing a woman nervously clutch her purse while in an elevator with an African-American man.
"I don't want to exaggerate this, but those sets of experiences inform how the African-American community interprets what happened one night in Florida. It's inescapable for people to bring those experiences to bear."
The president acknowledged that Florida's controversial "stand your ground" law was not actually cited as part of Zimmerman's defense. Nevertheless, Mr. Obama said that kind of law does not necessarily send a positive message.
"If we're sending a message in our societies ... that someone who is armed potentially has the right to use those firearms even if there is a way for them to exit from the situation, is that really going to be contributing to the peace and order?" he asked. "For those who resist that idea, I'd just ask people to consider if Trayvon Martin was of age and armed, could he have stood his ground on that sidewalk? Do we actually think he would've been justified in shooting Mr. Zimmerman because he followed him in a car?"
Finally, he said the nation shouldn't lose sight of its progress on issues of race and equality.
"When I talk to Malia and Sasha, and I listen to their friends and I see them interact, they're better than we are," he said. "That's true of every community that I've visited all across the country."