North Korea has said the United States must change its attitude in their nuclear negotiations ahead of the first anniversary of the Singapore summit between North Korean leader Kim Jong-un and U.S. President Donald Trump. 

In a statement issued late Tuesday, a spokesperson for the North's Foreign Ministry said that the U.S. should drop its current calculations and make a "correct strategic choice before it's too late."

The spokesperson said that Washington’s unilateral demand that Pyongyang dismantle its nuclear program was the reason for the collapse of their second summit in Hanoi.

Pyongyang stressed however that it remains committed to the faithful implementation of the June 12 North Korea-U.S. summit agreements, pointing to recent remarks made by leader Kim Jong-un in which he said he will wait for a “courageous decision” from the U.S. until the end of this year.  

The statement said the fate of the North Korea-U.S. joint statement signed in Singapore will be determined by how the U.S. responds to the North's calls, adding there is a limit to its patience.