WASHINGTON, Feb. 8 (Xinhua) -- U.S. President Donald Trump said on Friday that a second summit with top leader of the Democratic People's Republic of Korea (DPRK) Kim Jong Un is to be held on Feb. 27-28 in Hanoi, Vietnam's capital.

"My representatives have just left North Korea after a very productive meeting and an agreed upon time and date for the second Summit with Kim Jong Un. It will take place in Hanoi, Vietnam, on February 27 & 28," Trump tweeted, referring to U.S. special envoy for DPRK-related issues Stephen Biegun's DPRK visit.

"I look forward to seeing Chairman Kim & advancing the cause of peace!" he added.

"North Korea, under the leadership of Kim Jong Un, will become a great Economic Powerhouse," he later tweeted in a separate post.

"He (Kim) may surprise some but he won't surprise me, because I have gotten to know him & fully understand how capable he is. North Korea will become a different kind of Rocket -- an Economic one!" Trump said.

Earlier in the day, the State Department said in a statement that during his stay in the DPRK, Biegun had "met with Special Representative for U.S. Affairs of the State Affairs Commission of the D.P.R.K. Kim Hyok Chol February 6-8, in Pyongyang."

In his second State of the Union address made on Tuesday, Trump said that he will meet with Kim Jong Un on Feb. 27-28 in Vietnam, but did not disclose the specific location.

Biegun traveled to Pyongyang later on Wednesday to prepare for the summit, and to "advance further progress on the commitments the President (Trump) and Chairman Kim made in Singapore: complete denuclearization, transforming U.S.-DPRK relations, and building a lasting peace on the Korean Peninsula," the State Department said.

Trump met with Kim for the first time in Singapore on June 12, reaching several commitments, at least in principle, that have led to the improvement of the U.S.-DPRK relations. However, differences between the two sides on such key issues as the roadmap of denuclearization, U.S. sanction-lifting and whether to issue a war-ending declaration, still haunt the two sides and hinder negotiations.

On Jan. 30, Trump said that progress is "being made" in talks with Pyongyang and that he saw a "decent chance" of denuclearization on the Korean Peninsula.

On Jan. 31, Biegun said in a speech that the U.S. side expects to hold working-level negotiations with DPRK in advance of the summit, "with the intention of achieving a set of concrete deliverables ... a roadmap of negotiations and declarations going forward, and a shared understanding of the desired outcomes of our joint efforts," he said.

Trump also said on Tuesday that "as part of a bold new diplomacy, we continue our historic push for peace on the Korean Peninsula."

"Much work remains to be done, but my relationship with Kim Jong Un is a good one," he added.

But so far, there has been no comment from the DPRK on the issue.