Madonna walks between cars to avoid photographers at end of her visit to Kondanani orphanage in Bvumbwe

A children's rights groups in Malawi has called on the government to delay plans for American pop star Madonna to adopt a one-year-old boy.

The group Eye of the Child expressed concern Friday about the adoption process, saying it should not be like buying property. The group warned it may seek to block a court order this week granting interim approval for the adoption by Madonna and her husband, Guy Ritchie.

Under Malawi law, the couple's adoption will be reviewed for 18 months before the judge gives his final decision.

Madonna and her husband left the southern African nation Friday, ending a nine-day trip. But the one-year-old boy, David Banda, remained in the country because of ongoing legal procedures.

Madonna arrived in Malawi last week, in part to inspect an orphan care center she is funding near Lilongwe.