Japan's top court on Friday rejected an appeal by doomsday cult founder Shoko Asahara, a court official said, paving the way for his execution for a string of killings including the 1995 nerve-gas attack on Tokyo's subways.

The court upheld an earlier court decision finding that Asahara was competent to face justice, Kyodo News agency reported. The former guru's defense team had argued he was mentally unstable and did not understand the proceedings.

The nearly blind Asahara, born Chizuo Matsumoto, was convicted and sentenced to death in 2004 for masterminding attacks that killed 27 people, most chillingly the subway attack in which followers released sarin nerve gas on crowded commuter trains in Tokyo's government district, killing 12.

The Supreme Court voted to reject the former guru's appeal, said Naoki Katayama, a court spokesman, but he refused to say whether this would lead automatically to Asahara's execution.

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A Justice Ministry official, speaking on condition of anonymity because of ministry rules, said Friday's decision finalized the death sentence, but that Asahara's defense team could still forestall his execution by applying for a retrial or an emergency appeal.

If the defense team does nothing, Asahara will be executed within six months of receiving official court notice of Friday's ruling, the official said. The execution also requires the approval of the justice minister, he said.

Victims' advocates approved of the ruling.

"It's natural that Matsumoto was sentenced to die," Shuichi Kojima told reporters. Kojima worked in the same legal firm as an anti-cult lawyer murdered by Aum, Tsutsumi Sakamoto.

Asahara's lawyers did not immediately respond to calls by The Associated Press to their office and personal telephones.

But one of the lawyers, Akio Matsushita, said in a statement earlier this week that rejection of the appeal would be a "wrong decision that intentionally ignores the evidence and legal procedures that leaves a mark in the nation's legal history."

Asahara's group, which has renamed itself Aleph, issued a contrite statement Friday.

"Aleph deeply regrets the fact that we regarded Asahara as a god was at the root of these events," national broadcaster NHK quoted the statement as saying. "In the future, we hope to discover the way of the truth."

Calls to the cult went unanswered.

The Tokyo gassing was a severe psychological shock to Japan, a nation which had long prided itself on its orderly, highly secure society. The impact was heightened by the fact that the bearded guru had recruited graduates from some of Japan's most prestigious universities.

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Asahara ruled with an iron hand, bewitching followers with a mixture of Hinduism, Buddhism and yoga. Initiates paid large sums to drink Asahara's dirty bath water or sip his blood. The disobedient were killed and incinerated in a huge microwave oven at cult headquarters.

Flush with cash, the cult amassed an arsenal of chemical, biological and conventional weapons in anticipation of an apocalyptic showdown with the government.

Despite questions over Asahara's mental stability, there is little or no public support for scuttling his execution on humanitarian grounds. Deputy Chief Cabinet Secretary Jinen Nagase called the decision "appropriate."

Asahara was convicted in 2004 by the Tokyo District Court. The Tokyo High Court threw out his appeal in March 2006 after Asahara's lawyers missed an application deadline. The lawyers claimed they missed the deadline because Asahara was unable to express to them his wishes regarding his own defense.

The lawyers then filed objections to the High Court decision with the Supreme Court, and those objections were rejected on Friday.

Asahara's mental health has been a frequently raised issue by the defense. The former leader, who once commanded a cult of 40,000 members, often mumbled incoherently during his eight-year trial, interrupting sessions with bizarre outbursts in gibberish or in broken English. His lawyers say they have never been able to carry out a coherent discussion with their client.

But last month, a court-appointed psychiatrist determined that Asahara could be feigning mental illness, and said he is competent to stand trial.

In the final appeal, the lawyers claimed both the High Court decision to throw out the appeal and the mental evaluation were improper.

In addition to the subway attack, Asahara was convicted of plotting a 1994 gas attack in the central Japanese city of Matsumoto that killed seven people, the kidnapping and murder of an anti-cult lawyer and his family, and other slayings.

About a dozen other Aum leaders have been sentenced to death, but none have been executed. Most of their cases are still pending appeal in higher courts.

Japanese police suspect Aleph still follows Asahara's teachings, and the group is under close surveillance.