WASHINGTON — President Clinton has postponed for at least six months what would have been the first execution of a federal inmate in 37 years, leaving the fate of convicted murderer Juan Raul Garza for the next president to decide.

In deciding to stay the execution until June, Clinton said Thursday he wanted to give the Justice Department more time to gather and properly analyze information about racial and geographic disparities in the federal death penalty system.

"In issuing the stay, I have not decided that the death penalty should not be imposed in this case, in which heinous crimes were proved," Clinton said in a statement. "Nor have I decided to halt all executions in the federal system."

Clinton concluded that examining the possible racial and regional bias should be completed before the United States moves forward. "In this area, there is no room for error," Clinton said.

Clinton, who earlier postponed the inmate's scheduled execution from Aug. 5 to Dec. 12, has received a flurry of requests from here and abroad to spare Garza, a 44-year-old marijuana-ring boss convicted in Texas of three murders in 1990 and 1991. French President Jacques Chirac appealed in his role as president of the European Union, whose members generally oppose capital punishment. Pope John Paul II also sent a letter.

Garza received the news in a phone call from one of his lawyers.

"Juan is indeed relieved. His family is overjoyed," said Bruce Gilchrist, an attorney who also represents Garza.

He said Garza and his lawyers do not see how further study will change Garza's case, yet they hope to get favorable treatment from the next president.

"We hope that whoever is the next president will share Mr. Clinton's concern about the federal death penalty system and also recognizes that given the uncertainties that exist that it would be inappropriate to allow an execution," Gilchrist said.

Garza, a Hispanic from Brownsville, Texas, asked Clinton in September to commute his sentence to life in prison because of "long-standing racial bias" in capital punishment sentencing.

Of the 19 men under death sentence at the U.S. Penitentiary in Terre Haute, Ind., only four are white; the rest are minorities.

The president had unlimited power to act in the Garza case: He could have commuted the sentence to life in prison, issued a moratorium on all federal death sentences or refrained from acting at all, allowing the lethal injection to proceed as scheduled on Tuesday.

"Whether one supports the death penalty or opposes it, there should be no question that the gravity and finality of the penalty demand that we be certain that when it is imposed, it is imposed fairly," Clinton said.

Mervyn Mosbacker Jr., the Houston-based U.S. attorney for the Southern District of Texas who prosecuted Garza, declined to comment. "The issue will be under consideration by the incoming president, I do not feel it is appropriate to comment any further on the matter," Mosbacker said.

Clinton asked Attorney General Janet Reno to report to his successor by the end of April 2001 on the fairness of the federal death penalty. The death penalty is supported by both Vice President Al Gore and Texas Gov. George W. Bush, who has overseen more than 100 executions in his home state.

A previous Justice Department study found racial and geographic disparities in federal death sentences, which Garza's lawyers cited in a bid for clemency.

Deputy Attorney General Eric Holder has almost finished collecting data on federal cases which could have been charged as capital cases but were not, and Reno promised to quickly review any new data available. But another study by the National Institute of Justice, a research arm of the Justice Department, is unlikely to be completed until after the Clinton administration leaves office.

Clinton cited the results of the Justice Department study released this fall, which found that minority defendants and certain geographic districts are disproportionately represented in federal death penalty prosecutions.

"No one confronted with those statistics can help but be troubled by those disparities," Clinton said. "We do not, however, fully understand what lies behind those statistics."

Sen. Russ Feingold, D-Wis., said Clinton was right to delay the first execution since 1963, when Victor Feguer was hanged in Iowa for kidnapping and killing a doctor. But he said the president's action does not completely address flaws in the way the federal government administers the death penalty.

"A moratorium on all federal executions is the only full and fair response to a system that appears to be plagued with possible racial and regional disparities," Feingold said.

He added that he planned to reintroduce legislation next year calling for a moratorium on federal executions as well as an independent commission to review the system.

A Washington-based group called Citizens for a Moratorium on Federal Executions also was happy with the six-month reprieve, but said his decision falls short.

"We renew our call to the president to impose a moratorium on all federal executions," the group said in a statement.

Similar moratorium appeals have come from the Black Leadership Forum, a consortium of 26 civil rights organizations and leaders, the American Bar Association, the National Association of Criminal Defense Lawyers and some members of Congress.

But Clinton did not address calls to halt federal executions. And Reno responded Thursday as she had in September to a proposed moratorium: "I have not seen a basis for supporting it thus far."

On the Net:

Justice Dept. Survey of the Federal Death Penalty System: www.usdoj.gov/dag/pubdoc/dpsurvey.html