CBS News correspondent Ben Tracy was the only American broadcast news correspondent invited by North Korea to witness the destruction of a nuclear testing facility last week.

Tracy described the trip as secretive and full of strict rules, but reported officials said they wanted journalists at the site to be "transparent."

Tracy was not allowed to pull up the shades on his train window and had his radiation-testing equipment confiscated.

CBS News foreign correspondent Ben Tracy gave viewers a close-up look at the demolition of a nuclear testing facility in North Korea last week, a publicity-oriented trip he described as full of strict rules.

Tracy was the only American broadcast news correspondent out of around 20 invited by North Korea, he told Broadcasting & Cable. The only other American outlet present was CNN.

As detailed in his broadcast report shown on Sunday's "Face the Nation," Tracy and the other journalists traveled about 15 hours by train and car to see the demolition of the Punggye-ri Nuclear Test Site.

During the train ride, Tracy said he and his crew were forced to keep the window shades down, perhaps because the North Korean organizers didn't want the reporters to "see how people are living."

White-jacketed waiters served the journalists an "unexpected" 10-course meal aboard the train, a meal Tracy described as "somewhat uncomfortable, given most North Koreans live in poverty."

At the site of the demolition, officials made a spectacle of setting off explosives in view of the small crowd. Officials assured reporters at the site there was no risk of radiation. However, CBS could not verify the claim as officials had previously confiscated any devices that could be used to detect or measure radiation.

The journalists were allowed to spend 9 hours at the site as they destroyed three test tunnels, but Tracy pointed out that they had no way of telling for sure if the site was completely ruined for nuclear projects.

"The problem is, this is a group of journalists," Tracy said. "Nobody there is a nuclear expert, so we have no way of knowing if what they did in front of us actually does render that site completely unusable, or if it simply just destroyed the entrances to these tunnels that could then eventually be fixed."

Officials wanted journalists in the front row for the demolition for transparency's sake, and said the destruction of the site shows that "all they really want is peace," Tracy reported.

US officials are reportedly negotiating with North Korea after reports that leader Kim Jong Un is committed to "complete denuclearization" and a US summit. Last week, President Donald Trump canceled an upcoming summit with the Korean leader while the journalists were still in the country, citing "tremendous anger and open hostility" in North Korea's public statements.

Tracy previously reported from North Korea last year when he attended a military parade in Pyongyang. The parade was a display of North Korea's military weapons arsenal, an aggressive show that is now a stark contrast to this trip's described goal of "peace and stability" in the world.