Vatican City, Aug 17 (IANS): The Vatican broke its silence about a grand jury report that detailed decades of sexual abuse of thousands of children by over 300 priests in the US state of Pennsylvania, calling the accusations "criminal and morally reprehensible".

"Regarding the report made public in Pennsylvania this week, there are two words that can express the feelings faced with these horrible crimes: shame and sorrow," CNN quoted Greg Burke, director of the Vatican's Press Office, as saying on Thursday.

"The Holy See treats with great seriousness the work of the Investigating Grand Jury of Pennsylvania and the lengthy Interim Report it has produced. The Holy See condemns unequivocally the sexual abuse of minors."

This week, Pope Francis had been under increasing pressure to address a rapidly escalating sexual abuse crisis that has spread across several continents, from Australia to Latin America.

The Vatican's comments came 48 hours after the Pennsylvania report was released.

The report said internal documents from six Catholic dioceses in Pennsylvania -- some held in a secret archive to which only the bishop had a key -- show that more than 300 "predator priests" have been credibly accused of sexually abusing more than 1,000 child victims.

The lengthy report investigates clergy sexual abuse dating back to 1947.

According to the report, the accused priests victimised boys, girls, teens and pre-pubescent children.

Some victims were plied with alcohol and groped or molested while others were raped.

"The clock is ticking for all of us in Church leadership," CNN quoted Cardinal Sean O'Malley of Boston, the Pope's top adviser on sexual abuse, as saying on Thursday.

"Catholics have lost patience with us and civil society has lost confidence in us."

The Pope is yet to comment on the the nearly 900-page report.