U.S. President Donald Trump said on Tuesday that he has received a "beautiful" and "very warm" letter from North Korean leader Kim Jong-un.

Before leaving for a campaign trip to Iowa, Trump told reporters at the White House that he received the letter on Monday and that it was a “very personal, very warm, very nice letter.”

Trump said Kim and he have a good relationship together, adding he thinks something “very positive" will happen. 

He did not disclose the content of the message but added that he thinks North Korea has "tremendous potential" under the Kim regime.

When asked about recent reports that Kim's assassinated half-brother Kim Jong-nam once served as a CIA asset in North Korea, Trump said he wouldn't have let that happen under his auspices.