It is not known where the mother and son spent the past week

A US mother and her cancer-stricken son have returned voluntarily after fleeing Minnesota to avoid court-ordered chemotherapy for the 13-year-old boy.

Doctors checked Daniel Hauser after the pair returned on a charter flight from an unnamed location, an official said.

Colleen Hauser had said she wished to treat Daniel's cancer with natural methods, citing religious beliefs.

The Brown County sheriff said he had dropped an arrest warrant for Mrs Hauser, calling it a "good day".

Bruce Bostrom, the doctor who diagnosed Daniel's cancer in January, also said he was happy to hear of the boy's return.

"I'm delighted," Dr Bostrom told the Associated Press news agency. "I've been so worried that he was going to die... I've been praying for his safe return, so I think my prayers will be answered."

The mother and son failed to attend a court hearing on Tuesday after a court-ordered X-ray showed Daniel had a tumour in his chest.

Daniel underwent one round of chemotherapy in February, but stopped after that single treatment, citing religious beliefs.

He is diagnosed with Hodgkin's lymphoma, a highly curable form of cancer when treated with chemotherapy and radiation.

Doctors had warned that he would probably die without conventional treatment.

Speaking last week at the family's farm near Sleepy Eye - a town of 3,500 about 80 miles (130km) from Minneapolis - the boy's father appealed to his wife and son to return.

Anthony Hauser said the pair had fled without telling him their plans. He suggested they might have gone to California, en route to alternative cancer clinics in Mexico.