Koh expressed concerns over rising uncertainties due to escalating trade war between China and the US, and more recently Japan's strict export controls on South Korea.
Early this week, Japan promulgated a revised Bill to remove South Korea from its 'whitelist' of trusted trading partners, following the July 4 export control measures on three materials used in chips and displays, Yonhap news agency reported on Wednesday.
The action will be effective from August 28.
"We have secured three-four months stock of (smartphone) parts in the run-up to Japan's whitelist decision. Thus, it won't affect launches of Galaxy Note 10 and Galaxy Fold.
"When considering the fourth-tier vendors, it's hard to predict what will happen three-four months later. If (trade tension) is prolonged, it would inevitably affect (our business)," Koh said in New York.
The Galaxy Note 10 will go on sale on August 23 and the Galaxy Fold, Samsung's first foldable device, will hit shelves in select markets in September.
Koh shared frustration about the Galaxy Fold, whose original launch date was delayed due to durability issues raised by early reviewers. "If I can open my heart, you'll see it burned out," Koh said. "I think unknown things can come out when we try innovations," he said.
Samsung had prepared about 1 million foldable device units in the run-up to the April launch.
"Galaxy Fold will be released in limited units in 20 nations, including South Korea, this year," Koh said, without elaborating on the specific launch date. "It's important to bring meaningful innovation to the market. Launching a foldable phone ahead of Huawei is not our priority," he said.
The Galaxy Fold is expected to be showcased at the Internationale Funkausstellung (IFA) in Berlin, Europe's largest tech show, in September, alongside new phones by other brands.
Its smaller rival LG Electronics Inc plans to take the wraps off its latest flagship smartphone with an enhanced dual-screen during IFA. Its Chinese rival Huawei is also set to release 'Mate X' with a higher price tag in September to heat the competition in the premium segment.
( With inputs from IANS )