Liberal New York Times columnist Nicholas Kristof said he noticed "positive changes" in North Korea during his recent visit there, even though he admitted that some aspects of the country were unsettling.

In an op-ed published Thursday, Kristof said all of North Korea, led by Kim Jong Un, is prepped for war and that they are trained to believe that they would win it.

"Still, for all the shadow of possible war, North Korea has had some positive changes," he wrote. "The famine is over (although malnutrition still leaves one in four children stunted), the economy has developed and government officials are far more open and savvy than a generation ago. ... North Korea is no longer hermetically sealed, and South Korean pop music and soap operas are smuggled in on flash drives and DVDs from China (watching them is a serious criminal offense). There is also an intranet — a rigidly controlled domestic version of the internet — and students learn English from about the third grade."

Recent reports, however, have said that tightened international sanctions against North Korea, combined with a draught, have further worsened the country's economic conditions and threatened a new famine.

The United Nations said in a report published in March that almost three-quarters of North Koreans rely on food aid, most of the country lacks basic healthcare and nearly half of the population suffers malnutrition.

During his stay, Kristof used social media to share photos in which he appeared to be dining on pizza at a restaurant and visiting a theme park where he said North Koreans like to have "fun."

In recent weeks, tensions between the U.S. and North Korea have escalated after North Korea ratcheted up its military exercises, and the Trump administration placed a travel ban against the country.

Kristof said he and three other Times journalists "promptly" received exemptions for the ban from the State Department.

A State Department spokesperson said he could not address a specific waivers granted to individuals but said there are federal guidelines that allow exemptions to the travel ban, including, "An applicant who is a professional reporter and journalist whose trip is for the purpose of collecting and making available to the public information about the restricted country or area."

"I've been covering North Korea on and off since the 1980s," Kristof wrote in his op-ed, "and this five-day trip has left me more alarmed than ever about the risks of a catastrophic confrontation."