A Salisbury man who is serving a state prison term for pornography-related child abuse has pleaded guilty to a federal charge of sexual exploitation of children.

The defendant, George R. Bell, 40, entered the plea Monday to Judge William N. Nickerson in U.S. District Court in Baltimore. The judge set sentencing for July 26.

In return for the plea, Assistant U.S. Attorney Gregory Welsh agreed to drop four other pornography and interstate travel charges. But Welsh indicated he would ask Nickerson for an enhancement under federal sentencing guidelines that could bring Bell a no-parole prison term of at least 10 years.

Bell, arrested about a year ago on state charges, is serving concurrent 18-month state sentences in the Wicomico County Detention Center for pornography-related child-abuse convictions in Wicomico and Montgomery counties.

Welsh said in a statement of facts filed in court that Bell made videotapes of four nude girls, who ranged in age from 7 to 13, during a camping trip to Gettysburg, Pa., in June 1989, and took nude photos of a 7-year-old girl at his home in February 1990 while his wife and children were away.

The federal charges grew out of evidence in the two county cases.

Police affidavits filed in the Wicomico and Montgomery County circuit courts said Bell also took photographs of two 7-year-old Montgomery County girls in sexually explicit positions in their mother's bedroom during a visit to their home. The girls referred to Bell as "Uncle George," the affidavit said.