John McCain dies at 81 after battle with brain cancer
Sen. John McCain (R-AZ) delivering his Liberty Medal acceptance speech (image via screengrab).

Sen. John McCain (R-AZ) has died at the age of 81 after a battle with brain cancer.

The prominent senator was described as looking "increasingly frail" after surgery earlier this year for an intestinal infection, and he discontinued medical treatment for cancer Aug. 24.

He announced in July 2017 that he had been diagnosed with glioblastoma multiforme, an aggressive cancer.

McCain, who served in the U.S. Navy and was held prisoner during the Vietnamese War, was elected to the U.S. Senate in 1986.

He ran unsuccessfully for president as the Republican Party nominee in 2008, when he lost to Barack Obama.