BEIJING (AP) _ Children recruited into a war on pornography are turning in their bare- bottomed baby pictures, a newspaper said Wednesday.

Primary school students confused by the campaign's slogan - ''Sweep the Yellow'' - also are coming to school prepared to sweep streets and turning in yellow-covered books from their parents' bookcases, the official China Youth News said. ''Yellow'' ususally refers to pornographic material.

The ''yellow calamity has spread unchecked and has seriously harmed the spirit of our youth,'' the newspaper said. ''But this reporter feels that this campaign should not involve elementary school students.''

The report said some young pupils, told by teachers to turn in pornographic publications, asked what pornography was and were told it was pictures of people not wearing clothes.

Some obediently handed in their own baby pictures. Others brought in copies of Baby Pictorial, a magazine for young people, apparently because it had photos of naked infants.

''The teacher did not know whether to laugh or cry,'' the newspaper said.

It said even some teachers were not clear what qualified as pornographic literature and some students searched their homes for any books with a yellow cover.

Other pupils, told they were being organized into squads that would take to the streets Sunday to ''Sweep the Yellow,'' prepared themselves for a day of street-cleaning.

The official media carried similar reports this fall, citing cases of parents going out and buying pornographic books so their children could meet school quotas. One writer related that booksellers in his town were happy with their good sales of pornographic books and that children exchanged the books and read them with curiosity before handing them in.

Other children reportedly were bringing in calendars with pictures of female movie stars or any magazine with a woman's picture on the cover.

Authorities have confiscated millions of books, magazines and videos since the anti-pornography campaign began in August, destroying some in public burnings.

The banned books include works by dissident Fang Lizhi and other critics of the government who have been blamed for the pro-democracy protests - what the government calls the ''counterrevolutionary rebellion'' - of this spring.

The drive recently has been expanded into a campaign against prostitution, gambling, drugs, abduction and selling of women and children, and profiteering from superstition.