WINNIPEG -- A federal-provincial political spat has erupted over new freedoms granted to a Manitoba man found not criminally responsible for beheading a fellow passenger on a Greyhound bus.

Manitoba's senior federal cabinet minister, Shelly Glover, is criticizing a provincial Crown attorney for not opposing Vince Li's new privileges at a hearing earlier in the week. The privileges include Li's first unescorted trips from his mental hospital.

"The provincial decision to grant Mr. Li unescorted trips is wrong. We call upon Manitoba Attorney General Andrew Swan to appeal this decision immediately," Glover wrote in a statement Friday.

The province quickly accused Glover of trying to score political points by ignoring that politicians cannot tell Crown attorneys what to do.

"The attorney general of the province cannot, by law, intervene," acting justice minister Dave Chomiak said.

Li, 46, was found not criminally responsible for stabbing and beheading McLean, a young carnival worker, in July 2008.

The two men were strangers when Li sat next to McLean on a bus ride to Winnipeg from Edmonton. Li's attack was unprovoked -- he said he heard voices telling him to kill McLean. The bus stopped and horrified passengers fled as Li carved up McLean and ate parts of his body.

Li was initially kept inside a locked wing of the Selkirk Mental Health Centre for 24 hours a day. Each year the Criminal Code Review Board has granted him more freedoms at annual hearings into his case.

Following this year's hearing, the review board agreed with three requests from Li's psychiatric team, all of which were unopposed by the Crown:

-- That Li be granted unsupervised trips out of the mental hospital into the city of Selkirk.

-- That supervision on trips to other communities, including Winnipeg and nearby beaches, be reduced so that Li no longer has a staff member dedicated solely to supervising him in group settings.

-- That Li be moved from a secure wing of the hospital to an unlocked ward.

The Manitoba government expressed concern over the changes. Premier Greg Selinger said he is opposed to the unescorted day passes by Li.

"We would like to see more security for the public in these passes, yes," Selinger said from Toronto, where he was attending an energy conference.

But the review board is bound by federal law and, Chomiak said, it's up to Ottawa to change legislation to ensure public security takes precedence in any board decisions over the planned rehabilitation of an offender.

"The law is dictated by federal legislation. We have asked the government of Canada in writing, twice, to change it," he said.

"Shelly Glover could easily go down the hallway, talk to her colleague in the cabinet and have the law changed as we recommended ... to make safety a paramount concern."

Even if the provincial government stepped in to demand an appeal, it would be an uphill battle. Because the Crown did not oppose any of the changes to Li's conditions, it would essentially be appealing its own position.

Lead psychiatrist Dr. Steven Kremer said Li, a schizophrenic, has stopped experiencing delusions and is a model, non-violent patient.

Kremer also said Li always takes his medication and understands the importance of doing so.

Eventually, Kremer told the hearing, the aim is to reintegrate Li into society.