* Ombudsman says he could challenge sentence after appeal
* Says case is igniting tension in Russia
By Gabriela Baczynska
MOSCOW, Aug 23 (Reuters) - Russia's human rights ombudsman on Thursday called the prison sentences handed down to three women from punk band Pussy Riot "excessive" and warned that the case was igniting dangerous tensions within society.
The trio were convicted of hooliganism motivated by religious hatred by a Moscow court on Aug. 17 after belting out a profanity-laced anti-Putin song on the altar of Moscow's main cathedral in February
Vladimir Lukin, who was originally nominated for his advisory role by President Vladimir Putin, said he might challenge the sentencing of Nadezhda Tolokonnikova, Maria Alyokhina and Yekaterina Samutsevich if their jail terms were upheld on appeal.
"It is a misdemeanour that in a normal, civilised European state is handled in administrative rather than criminal proceedings. That's why I think the ruling on those women is excessive," he told a news conference when asked about the case.
Western governments and singers have condemned the sentences as disproportionate and the case has become a cause celebre in Western media where most commentators have echoed the Russian opposition's charge that the verdict was part of a crackdown on dissent by Putin.
However, the Kremlin has denounced foreign criticism as politically-motivated. Many Russian Orthodox believers have also said they were offended by the protest, part of a wave of demonstrations against Putin ahead of his re-election to the presidency in March for a third term.
The women said they meant no offence and were protesting against close ties between the state and the dominant Russian Orthodox Church, whose leader likened Putin's years at the helm to a "miracle of God" a few weeks before the Pussy Riot protest.
"POISONOUS SUBSTANCE OF INTOLERANCE"
Lukin, a former liberal lawmaker and ambassador to the United States, said the women's stunt was not a crime but a "quite serious misdemeanour".
He said he hoped an appeals court would "more carefully consider all the aspects of this case" and that as ombudsman he had the right to challenge the verdict once it entered into force if he believed human rights had been violated.
"If the sentence remains the same ... I will analyse this thoroughly," he said.
Lawyers for the women have said they expect to file an appeal next week.
His intervention in the debate came as The Nobel Peace Center, an arm of the Nobel Foundation, extended an invitation to members of Pussy Riot and their spouses to attend the Oslo World Music Festival in October, a symbolic gesture it said was meant to highlight Russia's poor human rights record.
The invitation was issued in conjunction with Amnesty International and the festival's organisers.
Lukin suggested the Pussy Riot case, which has inflamed emotions among both liberal and conservative Russians, was widening dangerous rifts in a society that has endured repeated upheaval over the past century.
"It is regrettable that a poisonous substance of intolerance and brutality is spreading in our society. Recently it has become typical and even fashionable not to discuss problems but to lash about at one another," Lukin said.
"The instinct for dialogue is fading and the fighting instinct is coming into the foreground. This is very dangerous."