North Korean media said last week that Mr Pae had admitted charges of crimes against North Korea, including attempting to overthrow the government.
“The Supreme Court sentenced him to 15 years of compulsory labour for this crime,” KCNA said.
Arrested at port
Mr Pae, 44, was arrested in November as he entered the northeastern port city of Rason, a special economic zone near North Korea’s border with China.
Bae is believed to be a devout Christian, according to human rights activists in South Korea, who say he may have been arrested for taking pictures of starving children, known as “kotjebi,” or fluttering swallows.
He was part of a group of five tourists who visited the north-eastern North Korean city of Rajin in November and has been held since then.
“We call on the DPRK [North Korea] to release Kenneth Bae immediately on humanitarian grounds,” US State Department spokesman Patrick Ventrell said on Monday.
Diplomats from Sweden, which represents the US in North Korea in the absence of diplomatic ties, had been providing counsel to Mr Pae, reports said. The US State Department was working with the Swedish embassy to confirm the report of the sentencing.