RICHMOND, April 1 -- Virginia Gov. Timothy M. Kaine announced Tuesday that he is halting all executions until the Supreme Court decides whether lethal injection violates the constitutional ban on cruel and unusual punishment.

Kaine's announcement came as he stayed the April 8 execution of Edward N. Bell, who killed a police officer in Winchester in 1999. Along with the reprieve, Kaine said future executions will be put on hold until the Supreme Court rules in the case of Baze v. Rees. The case was argued in January, and a decision could come before the court adjourns in June.

"In order to provide guidance to courts, litigants and the public, it is my intention . . . to grant a temporary delay of any execution date in Virginia that has been set," Kaine (D) said in a statement.

The decision prompted concern from Republicans that Kaine, who opposes the death penalty, is trying to work toward a permanent moratorium, a contention that administration officials deny.

Bell's execution date has been changed to July 24. The scheduled May 27 execution of Kevin Green, who killed a Southern Virginia convenience store owner in 1998, will also be put on hold, according to the state attorney general's office.

The decision could also delay the execution of Robert Yarbrough, who killed a convenience store owner in 1997. Yarbrough's execution date has not been set, according to the attorney general's office.

Kaine's decision is largely symbolic because the Supreme Court has not allowed an execution since it took up Baze v. Rees. The case centers on challenges from two death-row inmates in Kentucky who say that their Eighth Amendment rights would be violated if they were to die by lethal injection.

The District does not allow the death penalty, and Maryland has, in effect, had a moratorium on capital punishment since 2006, when Maryland's highest court ruled that state procedures for lethal injections had not been properly adopted. Maryland Gov. Martin O'Malley (D) has to issue new regulations, a step he has resisted. In recent weeks, both houses of the Maryland General Assembly have passed similar bills establishing a commission to study capital punishment.

In October, the Supreme Court stopped the execution of Virginia inmate Christopher Scott Emmett, who beat a co-worker to death with a brass lamp in Danville in 2001. Legal experts said the court's decision in that case signaled a nationwide halt to lethal injections until the justices decide Baze v. Rees.

Kaine said about 30 executions nationwide have been stayed since September, either by the Supreme Court, lower courts or governors. He said he is trying to instill more certainty in the process while officials await the court ruling.

"Stays in the final hours before an execution can take an emotional and physical toll on those who must prepare for the execution," Kaine said in explaining his ruling.

Richard Dieter, executive director of the Death Penalty Information Center, said several states, including Oklahoma, have stopped setting execution dates until the court rules.

"It is clear if you are going to have a lethal injection, you are going to have to wait until the Supreme Court rules, so there is no point in pushing it," Dieter said.

But Kaine's decision thrust him back into the debate over Virginia's use of capital punishment. Virginia trails only Texas in the number of executions carried out since 1976.

Although Kaine has allowed four executions to proceed, he has delayed several others since he took office in 2006.

Kaine has also twice vetoed legislation that would have made accomplices eligible for the death penalty. The legislation would have eliminated the "triggerman" rule, which says only a person who commits a killing in a capital murder case is eligible for the death penalty.

Last year, Kaine also vetoed a bill that would have made the killing of judges or witnesses a capital crime, arguing that Virginia already executes enough people. There have been 98 executions since 1976.

House Majority Leader H. Morgan Griffith (R-Salem) said that although he can understand Kaine's rationale for his vetoes, the governor's decision to halt scheduled executions goes against his campaign promise to carry out state law.

"It is a complete violation of his promise to the people of Virginia," Griffith said. "He said he would follow the law."

Griffith and Attorney General Robert F. McDonnell (R), an expected candidate for governor next year, said death-row inmates have the option of dying in the electric chair, although that option is rarely used.

"Death-row inmates affected by the governor's actions have yet to select a method of execution as Virginia law provides, and only lethal injection cases are at issue in the Baze case," McDonnell said. "A moratorium may unnecessarily delay justice in other Virginia cases."

But Douglas A. Berman, a sentencing expert at Ohio State University, said Kaine's action did not go far enough.

"If he wanted to be really bold, he could say, 'I am putting a moratorium on all executions for all of 2008,' " Berman said, "because even after the Supreme Court rules, we are going to have to take some time to figure out what it all means."