By this meeting the Holy Father is showing his deep concern

Vatican spokesman

Cardinal Roger Mahony of Los Angeles said he was looking forward to talks with the Pope which would be "open, frank and without limitations".

"A healthy dialogue with officials in the Vatican is essential to repairing the past damage and to create a more open and honest way of dealing with any type of misconduct within the Catholic Church for the future," he said in a statement.

Cardinal Mahony was blunt about the reason for the crisis talks

His comments came after the pontiff summoned 13 cardinals from the US to the Vatican to explain their role in a growing scandal which is considered the worst in the history of American Catholicism.

The Vatican said the meeting next Tuesday and Wednesday was meant to "restore security and serenity to the families and trust to the clergy and the faithful".

The BBC's Justin Webb says that as Cardinal Mahony was speaking the crisis deepened, with police in Los Angeles saying they had set up a unit of detectives to investigate allegations of child abuse after receiving 70 complaints involving 50 priests.

Those allegations now join more than 400 in the city of Boston, where the scandal first emerged.

Time for action

The archbishops of New York and Boston - traditionally the two most important posts in the Catholic Church in the US - have been under pressure to resign because of their alleged role in covering up cases of abuse involving priests.

The Archbishop of Milwaukee has also been accused of suppressing information about cases of alleged abuse.

Church authorities face similar accusations in St Louis, Florida, California, Philadelphia and Detroit.

The Catholic Church also faces similar allegations in a number of other countries, and last month the Pope made his first public denunciation of guilty priests.

Our correspondent says the scandal has severely undermined the credibility of the Church and clearly the Vatican now believes it has to take action.

Parish transfers

Boston Archbishop Bernard Law, 70, has been at the epicentre of the scandal.

Archbishop Bernard Law: Under pressure

He is accused of knowing that a few priests in his archdiocese were serial child molesters and not disciplining them - he simply moved them from parish to parish where they preyed on new victims.

Cardinal Law did not turn up to mass at his cathedral on Sunday because there were protesters outside the building and he said he thought they would disrupt the service.

He has come in for heavy criticism since former priest John Geoghan was convicted of child molesting.

Cardinal Law acknowledged that he transferred Geoghan to another parish, despite knowing of sexual misconduct allegations against the now-defrocked Boston priest.

Geoghan is believed to have abused more than 100 people over a 20-year period.

Extraordinary meeting

The scandals are also a huge financial burden for the church. They have settled out of court in many instances and the cost of that has been more than $1bn.

There is talk that some archdioceses will be bankrupted by the scandals.

Commentators believe that the Pope will have to get rid of a layer of the Catholic hierarchy, starting with Cardinal Law.

They say that a special meeting of cardinals from just one country is extraordinary, and only one similar meeting has been held before.

In 1989, the Pope summoned all the archbishops in the US to discuss tensions between American Catholics and the Vatican over remarriage for divorced Catholics and disregard for the church ban on artificial birth control.