US President Barack Obama has called for a full investigation into the killing of an unarmed black teenager by a neighbourhood watch guard.
In a press conference on Friday, the American president said "if I had a son he would look like Trayvon". Obama went on to call the fatal shooting of 17-year-old Trayvon Martin a "tragedy".
Obama, the first black president of the United States, also said the nation needed to do some "soul searching" to figure out what led to the death hoodie-clad teenager's death.
"When I think about this boy, I think about my own kids" Obama said.
Obama said that he welcomed investigations into Martin's death by both the US Justice Department and the governor of Florida.
Obama's announcement came hours after the police chief of the Florida town where Martin was killed said he would temporarily step down from his job, saying his role in the investigation had become too much of a distraction.
Sanford Police Chief Bill Lee had been heading the investigation into the killing of Trayvon Martin by George Zimmerman, who says he shot the 17-year-old in self-defence.
Police have declined to arrest Zimmerman, prompting a public outcry over Florida's "stand your ground" law, which allows for the use of lethal force in some instances of self-defence.
Thousands gathered on Thursday for a rally led by veteran civil rights activist Al Sharpton in Sanford, where Martin was shot dead.
“We want permanent justice!” said Sharpton. “We want Zimmerman in court with his hands cuffed behind his back!”
More than a million people have signed an online petition seeking Zimmerman's prosecution.
Lee, who had been in the post for less than a year, called himself a distraction and said it had become "apparent that my involvement in the matter is overshadowing the process."
"I must temporarily remove myself from the position as police chief for the city of Sanford. I do this in the hopes of restoring some semblance of calm to a city which has been in turmoil for several weeks," Lee said.
"It is my hope that the investigation will move forward swiftly and appropriately through the justice system and that a
final determination in this case is reached," he added.
Zimmerman's actions have been condemned by the National Sheriffs' Association which sponsors the US's nationwide neighbourhood watch programme, a crime prevention scheme that allows local volunteers to patrol the streets.
It said it had no record that the community involved was registered with the NSA programme, calling Zimmerman a "self-appointed neighbourhood watchman".
"The alleged participant ignored everything the Neighborhood Watch Program stands for and it resulted in a young man losing his life. "
- Aaron D Kennard, NSA executive director
“The alleged participant ignored everything the Neighborhood Watch Program stands for and it resulted in a young man losing his life. Our thoughts and prayers are with the family of Trayvon Martin during this terrible time,” said Aaron D Kennard, the NSA's executive director.
Norton Bonaparte, Sanford City manager, speaking at a press conference at City Hall, said he was starting a search for an interim police chief. Until someone is named, two current captains would head the police force of 140 officers, he said.
"What the city of Sanford wants more than anything else for the Trayvon Martin family is justice," Bonaparte said.
Lee's decision to step down came a day after he received a vote of "no confidence" by Sanford's city commissioners and follows calls for his resignation by civil rights groups angered over the police department's handling of the case.
Turner Clayton, president of the Seminole County National Association for the Advancement of Colored People (NAACP), said he was relieved to see Lee step aside.
"The city commission made a good start last night," he said. "Based on that, the chief had no other recourse but to remove himself. We hope it becomes permanent."
Lee previously said he had no choice but to let Zimmerman go free.
The 2005 "stand your ground" law allows someone in fear of "great bodily harm" to respond with deadly force, and removes any duty to retreat if possible to avoid confrontation.
On February 26, Martin was returning to a gated community from a convenience store when Zimmerman, carrying a licensed handgun in his role as a so-called neighbourhood watch captain, saw him.
He called police to report "a suspicious guy" and followed him despite the dispatcher's advice not to do so. Neighbours said they heard a scuffle, cries for help and then a gunshot.