CNN  — 

North Korea will not get any sanctions relief until it has demonstrated “verifiable and irreversible” steps to denuclearization, US Defense Secretary James Mattis said Sunday.

The comments come less than 10 days before a planned summit between US President Donald Trump and North Korean leader Kim Jong Un, a high-stakes meeting that the US hopes will lead to North Korean nuclear disarmament.

“We can anticipate, at best, a bumpy road to the negotiation,” said Mattis, who was speaking alongside South Korean and Japanese defense ministers at the Shangri-La Dialogue, an annual security summit in Singapore that draws government officials and academics from around the world.

“We must maintain a strong collaborative defensive stance so we enable our diplomats to negotiate from a strong position of strength in this critical time,” said Mattis.

“We must remain vigilant, and we will continue to implement all UN security council resolutions on North Korea. North Korea will receive relief only when it demonstrates verifiable and irreversible steps to denuclearization,” added Mattis.

On Friday, Trump confirmed that his on-again off-again summit with Kim would go ahead on June 12, in a remarkable about-turn following a pre