BEIJING, Sept. 28 (Xinhua) -- Negotiators have made progress in discussing technical complex issues to denuclearize the Korean Peninsula, said U.S. envoy Christopher Hill Friday evening.

"For me it is a very useful day because we were able to discuss some real specifics" including the scope of disablement of the nuclear facilities of the Democratic People's Republic of Korea (DPRK), Hill told reporters after ending the second day of discussions of the second phase of the sixth round six-party talks.

"I think we've made a lot of progress in discussing a lot of very technical complex issues," Hill said.

"We're into a stage of this process beyond anything that's been done before," Hill said.

He said a road map for steps in the second phase of DPRK's denuclearization is necessary, and negotiators "were discussing real elements of what the road map would look like."

However, he said "we might not go with a joint statement" since it might be too time-consuming.

The DPRK has given the other delegations a date when they could first see the declaration, said Hill, but he refused to reveal the date.

The U.S. didn't hold any bilateral meetings with the other parties on Friday.

The talks that involve China, the United States, the DPRK, the Republic of Korea, Russia and Japan, began on Thursday and is scheduled to run through Sunday.

The first phase of the current round of the talks was held in March, which was concluded with a chairman statement.