Online video footage shows a man believed to be Zhu Xianjian being carried away by four police officers.
The coats are recognized in the hermit kingdom as "a symbol of power," a source told Radio Free Asia
The joint military exercises, which typically take place twice a year, have long been a source of tension between Pyongyang, Seoul and Washington.
Kim Jong-un recently admitted the food situation in North Korea is "getting tense" as imports from China have dropped 90 percent.
Kim Yo Jong said the U.S.. had "wrong" expectations after national security adviser Jake Sullivan expressed optimism for over talks with Pyongyang.
"We continue to hope that the DPRK will respond positively to our outreach and our offer to meet anywhere, anytime without preconditions," Kim said.
The ban reportedly came after a high-level official who was part of the country's economic bureaucracy died after receiving a Chinese-produced medicine used to treat fatigue.
Kim gave a speech during festivities marking the 75th anniversary of the Workers' Party of Korea.
China has sent a medical team to assess the health status of the supreme leader, Reuters reported.
Officials warned that such a move could crash the South Korean stock market, but the president reportedly ordered staff, "Go do it!"
Pyongyang tested the Pukguksong-3 ballistic missile on Wednesday, ahead of the resumption of disarmament talks with the U.S. this weekend.
Dan Smith of the Stockholm International Peace Research Institute suggested nuclear weapon development was continuing despite rapprochement with the U.S.
The man confessed to the sale, telling police: "I thought [North Korean beer] could be sold at a high price."
Trump became the first U.S. president to set foot in North Korea on Sunday when he crossed the border with Kim.
The 29-year-old has been living in Pyongyang since 2018 and is one of the few foreigners studying at the Kim Il Sung University.
The North Korean official referred to Bolton as more of a "security-destroying adviser" than a security adviser.
North Korea has accused the secretary of state of "talking nonsense" and "fabricating stories."
The deal would have allegedly seen Russia operate the plant and ship all nuclear waste back to Russia as a guarantee that the material couldn't be used to make weapons.
"Clothing made from artificial flannelette fabrics composed of trace elements such as high-grade protein, amino acids, fruit juice, magnesium, iron and calcium," read a translated spread from a men's fashion magazine.
Intelligence officers have been investigating the senior civil servant since last March.
The North Korean leader wants more assurances from the U.S.
"Portraits, slogans and posters form the core of a message for a socialist country," says Yang Moo-jin, a professor at the University of North Korean Studies.
The two Korean leaders said they had "agreed on a way to achieve denuclearization."
"We will both prove everyone wrong!" Trump said of himself and Kim Jong Un on Twitter. "There is nothing like good dialogue from two people that like each other! Much better than before I took office."
"The safety and security of U.S. citizens overseas is one of our highest priorities," a State Department official said.
Skepticism over North Korea's intentions mounts.