His family said he has "surpassed expectations for survival"

US Senator and former presidential candidate John McCain will no longer receive treatment for brain cancer, his family has announced.

The Arizona senator has been battling an aggressive form of the disease for more than a year.

His family says the 81-year-old has surpassed expectations for survival.

In a statement today, they said: "The progress of disease and the inexorable advance of age render their verdict. With his usual strength of will, he has now chosen to discontinue medical treatment."

"Our family is immensely grateful for the support and kindness of all his caregivers over the last year, and the continuing outpouring of concern and affection from John's many friends and associates, and the many thousands of people who are keeping him in their prayers."

Senator McCain - who was held as a prisoner of war during the Vietnam War - is currently serving his sixth term as senator.

He was chosen as the Republican candidate for the presidential election in 2008, but lost to Barack Obama.

While he has not been actively involved in the Senate since late last year, he has continued making public statements - including referring to President Trump's press conference with Vladimir Putin last month as "one of the most disgraceful performances by an American president in memory".