US Secretary of State Mike Pompeo says there is a “real opportunity” for a deal when President Trump meets the North Korean leader Kim Jong-un.
Interviewed by ABC News, he said North Korea must take “irreversible” steps to get rid of its nuclear arms programme.
Mr Pompeo met Mr Kim secretly in Pyongyang earlier this month as CIA director. Details only emerged later.
Mr Trump is expected to meet the North Korean leader next month to discuss denuclearising the Korean peninsula.
Mr Pompeo said Mr Trump had clearly told him to raise the issue of a verifiable mechanism to make sure North Korea does denuclearise. He also raised the topic of US citizens held by the North Koreans.