Image caption Monsignor William Lynn was convicted of enabling one priest to carry on abusing

US Roman Catholic Monsignor William Lynn has been sentenced to three to six years in jail for covering up a sex abuse complaint against a priest.

Lynn supervised hundreds of priests in his role as secretary for clergy at the Archdiocese of Philadelphia.

Last month he became the most senior clergyman convicted in connection to the US Roman Catholic Church scandal.

Judge M Teresa Sarmina said Lynn enabled "monsters in clerical garb... to destroy the souls of children".

"You knew full well what was right, Monsignor Lynn, but you chose wrong," the judge said.

'Strong signal'

Lynn was found guilty of endangering the victim of Edward Avery, a former priest convicted in 1999 of sexual assault.

He had declared Avery guilty of an earlier complaint by 1994, and helped steer him into a treatment programme. But he also knew that Avery was later sent to live in a new parish, where he assaulted an altar boy.

"I did not intend any harm to come to [Avery's victim]. The fact is, my best was not good enough to stop that harm," Lynn said. "I am a parish priest. I should have stayed [as one]."

The sentence handed down was less than the maximum seven-year penalty prosecutors had sought for Lynn's conviction on one count of child endangerment.

"I think this is going to send a very strong signal to every bishop and everybody who worked for a bishop that if they don't do the right thing they may go to jail," Reverend Thomas Reese, senior fellow of the Woodstock Theological Center at Georgetown University, told the New York Times .

Lynn was found not guilty of another charge of child endangerment and conspiracy.