It is an "open question" whether or not US athletes will participate in the 2018 Winter Olympics in South Korea amid rising tensions with North, the US ambassador to the UN has said.
Nikki Haley told Fox News that the US would take "every precaution" to ensure the safety of its athletes.
"We have to watch this closely, and it's changing by the day," she said.
The Games will be held in Pyeongchang, just 50 miles (80km) from the border that separates the North and South.
North Korea has received global condemnation for a series of missile tests.
The US military flew a B-1B bomber over South Korea on Wednesday as part of a massive joint aerial drill, in a move seen as a warning to the North.
On 29 November, North Korea said it had successfully tested a new type of intercontinental ballistic missile (ICBM) that could reach the whole of continental United States.
Despite the tensions, Ms Haley said the Trump administration would try and "find out the best way" to ensure athletes who attended the Games were protected.
"We will make sure that we're taking every precaution possible to make sure that they're safe, and to know everything that's going on around them," she said.
This follows the announcement that Russia is banned from next year's Winter Olympics.
The International Olympic Committee announced the ban after a 17-month investigation into state-sponsored doping in Russia.
The Games will be held 9-25 February 2018.