US president Barack Obama has made his first public comments on the Trayvon Martin case, saying that 35 years ago he could have been the unarmed black teen who was shot dead by a neighbourhood watchman.

In a surprise appearance before reporters, Mr Obama hailed the "incredible grace and dignity" of Martin's parents and said that resorting to violence in the wake of the Florida court verdict would "dishonour" his death.

The president also called for a review of controversial "stand your ground" laws like the one in place in Florida, which assert that citizens can use lethal force - rather than retreat - if they sense their lives are at risk.

Mr Obama did not comment directly on the jury's decision to acquit neighbourhood watch volunteer George Zimmerman, but did weigh in on the larger issues of the case.

"Trayvon Martin could have been me, 35 years ago," he said.

"I 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 that he would have been justified in shooting Mr Zimmerman, who had followed him in a car because he felt threatened?

"If the answer to that question is at least ambiguous, then it seems to me that we might want to examine those kinds of laws."

Verdict raises questions over racial profiling

Martin, 17, was fatally shot on the rainy night of February 26, 2012 during an altercation with the Mr Zimmerman, 29, in a gated community in Sanford, Florida.

Zimmerman said he acted in defence and his team did not specifically invoke the "stand your ground" law in its arguments.

A jury of six women, all but one white, cleared him of second-degree murder and manslaughter charges.

Critics of the verdict argue that Mr Zimmerman racially profiled the youth - who had no criminal record - and was able to kill him with impunity because of a biased criminal justice system.

Mr Zimmerman - who has a white father and a Peruvian mother - has insisted race was not a factor in the incident.

Mr Obama said African Americans are angered by the case because they see it through "a set of experiences and a history that doesn't go away".

"There are very few African American men in the country who haven't had the experience of being followed when they were in a department store. That includes me," he said.

"[There are] very few African American men who haven't had the experience of walking across the street and hearing the locks click on the doors of cars."

Mr Obama also urged better training of law enforcement at the state and local levels "to reduce the kind of mistrust in the system that sometimes currently exists."

ABC/AFP