ORLANDO, Fla. -- The neighbourhood watch volunteer who killed an unarmed black teenager was released from a Florida jail Friday for a second time while he awaits his second-degree murder trial in a case that inflamed racial tensions.

George Zimmerman, who has pleaded not guilty and claims he shot 17-year-old Trayvon Martin in self-defence, left the Seminole County Jail a day after a judge granted a $1 million bail with strict conditions.

The neighbourhood watch leader had been released on a $150,000 bond in April, but Circuit Judge Kenneth Lester revoked it last month after prosecutors presented evidence that he and his wife misled the court about how much money they had available to pay for the bond. They didn't tell the judge that donations from a website for Zimmerman's legal defence had raised around $135,000 at the time of his first bond hearing.

Zimmerman is required to stay in Seminole County. He must be electronically monitored, can't open a bank account, obtain a passport or set foot on the grounds of the local airport. He has a 6 p.m. to 6 a.m. curfew.

"He's very happy to be out," said Don West, one of Zimmerman's attorneys. "Certainly it's been a sobering experience being in that kind of environment."

Shortly before Zimmerman's release, the Rev. Al Sharpton criticized him for raising money through online donations. The civil rights leader was in New Orleans with Martin's parents, Tracy Martin and Sybrina Fulton.

Zimmerman will stay in a "safe house" before relocating to a permanent home, and he has hired a security team, according to information posted on a website run by his legal team.

Prosecutors argued Zimmerman and his wife talked in code during recorded jailhouse conversations about how to transfer the donations to different bank accounts. For example, George Zimmerman at one point asked how much money they had. She replied "$155." Prosecutors allege that was code for $155,000. Their reference to "Peter Pan" was code for the PayPal system through which the donations were made, prosecutors said.

Shellie Zimmerman faces arraignment at the end of the month on a perjury charge; she was freed on bond.

"Now, we see they are soliciting money!" Sharpton said.

During Zimmerman's second bond hearing, his attorney, Mark O'Mara, said that his client was confused, fearful and experienced a moment of weakness when he and his wife misled the court.

The judge didn't buy it and expressed his unhappiness with Zimmerman and his wife in his second bond order. He accused Zimmerman of making plans to flee to avoid prosecution, misleading O'Mara by not disclosing the money from the website and trying to manipulate the judicial system.

But the judge said current law limited his ability to deny a second application for bond.

Zimmerman claims the February shooting was self-defence under the state's "stand your ground" law. Zimmerman and Martin got into a fight inside a gated community in Sanford, Florida. Zimmerman was the neighbourhood watch leader for the community and Martin was visiting his father's fiance, who lived there.

The "stand your ground" law allows individuals to use deadly force provided they are doing nothing illegal and relieves them of a duty to retreat if they believe their lives are in jeopardy. The law allows defendants to make their self-defence case at a hearing presided over by a judge and without the use of a jury. If the judge deems self-defence was justified, the case can be dismissed without going to trial.

The 44 days between the shooting and Zimmerman's arrest inspired nationwide protests, led to the departure of the local police chief and prompted a U.S. Justice Department probe.

Martin's parents and supporters claim that the unarmed teenager was targeted because he was black and that Zimmerman started the confrontation that led to the shooting. Zimmerman's father is white and his mother is Hispanic.