A federal grand jury has issued a new 24-count indictment against a 20-year-old Oklahoma City man who is accused of sexually abusing children at a Kenya orphanage.

The indictment was returned Friday against Matthew Lane Durham of Edmond.

Prosecutors allege Durham engaged in sex acts with as many as 10 children ages 4 to 10 while volunteering at the Upendo Children's Home near Nairobi from April to June 2014.

Durham was named in a three-count indictment in August that accused him of traveling with intent to engage in illicit sexual conduct, engaging in illicit sexual conduct in foreign places and aggravated sexual abuse with children. The new indictment expands those charges by adding alleged victims.

Durham's attorney, Stephen Jones, says he is innocent.