By Daniel Burke, CNN Belief Blog Editor

(CNN) - The Vatican announced on Tuesday that it has placed a former ambassador under house arrest while he faces charges for "serious acts of abuse of minors."

Jozef Wesolowski is accused of molesting young boys during his stint as the pope's official representative in the Dominican Republic. Wesolowski had been appointed to the post in 2008 by Pope Emeritus Benedict XVI.

The former envoy, who was defrocked by the Vatican in June, is one of the highest-ranking church officials to be accused of abusing children during the Catholic Church's widespread and costly sexual abuse scandal. It is the first time a top Vatican ambassador has faced such charges.

Wesolowski's arrest, the Vatican said Tuesday, "is a result of the express desire of the Pope, so that a case so serious and delicate would be addressed without delay."

Francis has pledged to maintain a policy of "zero tolerance" for Catholic clergy who abuse children.

Wesolowski's case provides a high-profile chance for the Pope, who has been accused by some victims' groups of downplaying the sexual abuse scandal, to take concrete action against one of the Vatican's own.

The Vatican said that Wesolowski suffers from an unnamed but medically documented health condition, and will be placed under house arrest in Vatican City, which is a sovereign state.

Pressure had been building on the Vatican to proceed with criminal charges against Wesolowski, a Polish native ordained by Saint John Paul II, since the accusations against him became public.

That pressure intensified when The New York Times reported last month that Wesolowski had been seen walking freely about Rome.

The United Nations Committee Against Torture has also urged the Vatican to move swiftly on Wesolowski. A report by the committee in May noted that Poland had reportedly asked for the archbishop's extradition.

Under Vatican law, Wesolowski, if found guilty, could face a maximum sentence of 12 years in prison.