The United States on Wednesday said it is prepared to be flexible in talks with North Korea but warned the regime it must avoid provocations.

U.S. Ambassador to the UN Kelly Craft made the remarks at a Security Council session on North Korea, saying the U.S. remains ready to take concrete, parallel steps with North Korea towards an agreement.

Craft added, however, that the U.S. cannot do this alone and North Korea must make a "difficult but bold decision" to work with the U.S. 

The U.S. envoy also voiced concern that North Korea was indicating it would test intercontinental ballistic missiles designed to attack the continental United States with nuclear weapons. 

She said that the North's continued ballistic missile testing is "deeply counterproductive" to the shared objectives that the leaders of the two nations have discussed at their summits. 

She added the U.S. trusts North Korea will turn away from further hostility and threats and instead engage with the U.S.

Craft appeared to rule out meeting the North's demands that Washington change what it brings to denuclearization negotiations by the end of the year, saying that the U.S. and the Security Council "have a goal, not a deadline."