The Vatican has been given another hostile interrogation by a United Nations committee over its record on clerical sex abuse.

One member after another of the committee against torture brushed aside the Holy See's argument that its obligation to enforce the UN convention against torture stopped at the boundaries of the world's smallest country, the Vatican City state. They demanded the pope's representative give answers to a long list of questions about the treatment of sex abuse claims against clergy throughout the world.

The Holy See, which long predates the city state, is a sovereign entity without territory. It is as the Holy See that the Catholic leadership maintains diplomatic relations and signs treaties such as the convention against torture.

But Archbishop Silvano Tomasi, the Vatican's UN ambassador in Geneva, told the committee: "The Holy See intends to focus exclusively on Vatican City state."

The American expert on the committee, Felice Gaer, made plain her disagreement. She said the Holy See had to "show us that, as a party to the convention, you have a system in place to prohibit torture and cruel, inhuman and degrading punishment when it is acquiesced to by anyone under the effective control of the officials of the Holy See and the institutions that operate in the Vatican City state".

Gaer described the line that church officials sought to draw between the treaty obligations of the city state and the Holy See as an "alleged distinction".

She demanded responses to claims that Italian bishops had been told they were not under any obligation to report suspected cases of sex abuse to the civil authorities, as well as to allegations that the Vatican had given refuge to a papal envoy accused of sex abuse. In January, a Polish prosecutor said Warsaw had turned down a request for the extradition of Archbishop Jozef Wesolowski, who faces accusations of sex abuse in his Poland and in the Dominican Republic.

But Gaer, the director of an American-Jewish human rights organisation, the Jacob Blaustein Institute, said the church's doctrine on abortion was an area of legitimate concern for the committee. She called for the Vatican to comment on allegations that its blanket stigmatisation of abortion had led to nine-year-old girls being required to give birth.

In February, the Vatican reacted with outrage when another UN panel argued that children around the world were suffering from Catholic teachings, including those on abortion and birth control. The Vatican said comments by the committee on the rights of the child constituted an attack on religious freedom.

The issue of sex abuse was raised on Monday by committee members from Mauritius and Morocco and by George Tugushi, from Georgia. He welcomed a new committee to advise the pope, saying it could "begin to change the climate of impunity". But he added: "It cannot be considered in our opinion as a substitute for a functioning investigative system of the Holy See's or Vatican City state's own."

Tugushi also questioned the treatment of Paolo Gabriel, the previous pope's butler who was arrested for leaking papal correspondence. Gabriel said his eyesight had suffered from being kept in a cell where the light was kept on 24 hours a day and that he was given no opportunity to exercise.