SANFORD, Florida (Reuters) - A Florida judge said George Zimmerman was a flight risk and set bond at $1 million on Thursday for the neighborhood watch volunteer who shot and killed unarmed black teenager Trayvon Martin.

Zimmerman had been released on $150,000 bond but was sent back to jail in June after prosecutors alleged he misled the court about his finances and failed to surrender a valid passport.

"This court finds that circumstances indicate that the defendant was preparing to flee to avoid prosecution, but such plans were thwarted," said Circuit Judge Kenneth Lester, who credited an electronic ankle bracelet with blocking Zimmerman's plans.

The judge said the higher bond was necessary to ensure Zimmerman would show up for trial on second-degree murder charges.

"The increased bail is not a punishment; It is meant to allay this court's concern that the defendant intended to flee the jurisdiction and a lesser amount would not ensure his presence in court," Lester wrote in his eight-page order.

The judge imposed numerous restrictions. He said that if released from jail again, Zimmerman must submit to electronic monitoring, remain in Seminole County, stay away from the Orlando-Sanford International Airport, refrain from applying for a passport or opening or maintaining a bank account, avoid alcohol and obey a curfew from 6 p.m. to 6 a.m.

Defense attorney Mark O'Mara told Reuters that Zimmerman does not have the cash or collateral to post the new bond.

"We have to do some very intentional fundraising to help the defense fund and to help George because he's not getting out without a lot more fundraising," O'Mara said.

He called the judge's order "very pointed," and said, "The judge obviously is very upset with George, believing that this thing was orchestrated. I disagree with that."

Ben Crump, the lawyer for Martin's family, said the judge sent a strong message.

"Just because you claim to be scared and confused, you can't lie and manipulate and mastermind this scheme," Crump said. "Money and a passport are the essential elements to flee. The judge saw this like everybody else in America saw it."

Zimmerman is charged in the February 26 shooting death of 17-year-old Martin in a gated community in the central Florida city of Sanford.

Martin's killing drew national attention because police initially failed to arrest Zimmerman. They cited Florida's "Stand Your Ground" self-defense law and Zimmerman's claim that he used deadly force because he believed his life was being threatened by Martin.

Zimmerman, 28, was later arrested on second-degree murder charges, which carry a penalty of 25 years to life in prison.

At his first bond hearing on April 20, Zimmerman sat silently as his wife told the court the couple had no money.

Shellie Zimmerman was charged with perjury after investigators learned the couple had raised at least $135,000 from a PayPal account set up to collect donations for Zimmerman's legal defense and living expenses.

The two were recorded during jail house phone calls in which they discussed moving the money among accounts, transactions that prosecutors called a deliberate attempt to deceive.

Prosecutor Bernie De La Rionda said that showed Zimmerman was untrustworthy and asked that he be denied bond.

O'Mara, the defense attorney, had argued that Zimmerman posed no risk of harm to the community and portrayed the case against him as weak.

The judge's order was scathing in its complete rejection of that argument.

It cited the prosecutor's contention that Zimmerman's "stories changed with each retelling." It also said the strength of evidence against Zimmerman was irrelevant to whether he should be awarded bond after misleading the court about his finances.

"Under any definition, the defendant has flaunted the system," the judge wrote.

The judge said O'Mara had attempted to portray Zimmerman as a confused young man who "experienced a moment of weakness" and may have acted out of a sense of betrayal by the justice system.

"This court finds the opposite. The defendant has tried to manipulate the system when he has been presented the opportunity to do so," the judge wrote.

He noted that Zimmerman had previously been arrested and completed a pretrial diversion program after a fight with a state alcohol agent, had filed for and been the subject of court-ordered domestic injunctions and had taken courses in criminal justice.

The judge said Zimmerman had a "very sophisticated knowledge of the criminal justice system over and above that of the average law-abiding citizen."

The money raised for Zimmerman's defense has since risen to more than $200,000 but was under the control of an independent trustee.