US Republican Senator John McCain has a malignant tumor in the brain, reported by the office and his family, quoted by Reuters and Associated Press.

The diagnosis has been made during a blood clot removal surgery in his left eye, made this week at Mayo Clinic Hospital in Phoenix, Arizona, CNN reported. According to the Television network, it took some time after the surgery to make a histological analysis of the find, which turned out to be a primary malignant brain tumor, glioblastoma, a very aggressive type that is difficult to cure.

McCain is a former military pilot, a veteran of the Vietnam War, whose plane was shot down over North Vietnam during a 1967 Hanoi bombing, and he spent seven years in Vietnamese captivity. After his dismissal from the US Air Force in 1981, he spent two terms in the House of Representatives, and since 1986 he has been a senator. McCain twice ran for President of the Republican Party and was a rival to Barack Obama in the 2008 election.

'John McCain is an American hero & one of the bravest fighters I've ever known. Cancer doesn't know what it's up against. Give it hell, John.' - wrote the previous president on Twitter as a message of support.