Former US President Jimmy Carter has revealed he is to be treated for cancerous tumours on the brain, in his first public comments on his illness.

Mr Carter said he would undertake radiation treatment.

Mr Carter, 90, was recently treated for liver cancer, after which it was discovered the disease had spread.

He said he would “cut back fairly dramatically” on public works. “It is in the hands of God and I am prepared for anything that comes,” he said.

A Democrat from Georgia, Mr Carter was a relative unknown in the US political world when he was elected president in 1976. He served from 1977 to 1981.

‘No pain’

Mr Carter told a press conference on Thursday he had at first thought the cancer was confined to his liver and that an operation this month had completely removed it.

But an MRI scan the same afternoon showed four spots of melanoma on the brain.

“I just thought I had a few weeks left, but I was surprisingly at ease. I’ve had a wonderful life,” he said.

“I have got thousands of friends and I have had an exciting and adventurous and gratifying existence.”

Mr Carter said it was likely doctors would find cancer elsewhere in his body as his treatment continued.

But he said: “I feel very good. I have had no pain or debility.”

Since leaving the White House in 1981, Mr Carter has remained active, carrying out humanitarian work with his Carter Center in recent years.