A North Korean diplomat said Friday that the window of opportunity for progress in dialogue with the United States was getting smaller, adding that Pyongyang expects reciprocal steps from Washington by the end of the year.

"We've given the United States quite a lot of time and we're waiting for an answer by the end of this year, of some kind of result. ... But I must say that the window of opportunity closes every day," said Jo Chol Su, the head of the North Korean Foreign Ministry's North American department.

Jo, who spoke at the Moscow Nonprofileration Conference, said Pyongyang was ready to hold talks with the United States if there was the prospect of progress, but was not interested in dialogue that would yield no results, Russia's Interfax news agency reported.