The so-called Islamic State (IS) claims to have captured two hostages from Norway and China, and the militant group is soliciting ransom payments for the men in the latest issue of its English-language propaganda magazine.

IS identified the men as Ole Johan Grimsgaard-Ofstad, 48-year-old from Oslo, and Fan Jinghui, a 50-year-old from Beijing.

Full-page, advertisement-style listings in the group's Dabiq magazine show pictures of both men and say they are "for sale." The images list a "telegram number" for "whoever would like to pay the ransom for his release and transfer."

This image has been edited to remove some identifying details and other information.

Telegram may refer to the secure messaging app that lets users instantly message friends or strangers without necessarily knowing their number.

The militants provided no details about when or where the hostages were captured.

Fan's listing in Dabiq describes him as a "freelance consultant."

On January 18, Grimsgaard-Ofstad posted a photo on his Facebook account that appeared to show him in Turkey near the Syrian border. Six days later, the Norwegian posted another update saying he had reached the northwestern Syrian province of Idlib. "I finally made it," he wrote.

This image has been edited to remove some identifying details and other information.

Norwegian Prime Minister Erna Solberg confirmed on Wednesday that one of the country's citizens had been taken hostage in Syria.

"Our goal is to get our citizen home," she said at a news conference. "Let me be very clear — this is a very demanding case."

She did not identify the hostage by name, but said he was in his 40s and had been held by several groups since he was first captured.

"The government is taking this very seriously," she said. "We cannot and will not give in to pressure from terrorists and criminals. Norway does not pay ransoms. That is a principle we cannot give up in meetings with cynical terrorists."

A ransom payment would increase the risk of other Norwegian citizens being kidnapped, she said.

Solberg declined to take questions from the media at the news conference, and withdrew from a televised party debate in the run-up to local elections that are scheduled for Monday.

A Norwegian government crisis group is working on the hostage case, the prime minister said.