U.S. President Donald Trump participates in an American Workforce Policy Advisory Board meeting in the White House State Dining Room in Washington, U.S., March 6, 2019. Reuters-Yonhap

U.S. President Donald Trump said Wednesday he would be "disappointed" if reports that North Korea is rebuilding a missile engine test site are true.

Trump made the remark at the White House when asked about two U.S. reports that North Korea is rebuilding the Sohae satellite launching facility, which it began to dismantle last year.

"I would be very disappointed if that were happening," he told reporters. "It's a very early report. We're the ones that put it out. But I would be very, very disappointed in Chairman Kim, and I don't think I will be."

"We'll take a look," he said. "It'll ultimately get solved."

Trump and North Korean leader Kim Jong-un held their second summit in Hanoi, Vietnam, last week to negotiate a deal on dismantling the regime's nuclear weapons program in exchange for sanctions relief.

'Pyongyang still running uranium enrichment facilities' 2019-03-07 11:03  |  North Korea Seoul, Washington, Tokyo to continue joint nuclear efforts 2019-03-07 10:13  |  North Korea North Korea rebuilding long-range rocket site: spy agency [PHOTOS] 2019-03-06 11:28  |  North Korea 'Spy chief may visit North Korea soon to revive nuke talks' 2019-03-06 17:16  |  Politics All eyes on Kim Jong-un's next step 2019-03-06 18:12  |  Politics US may ramp up sanctions: Bolton 2019-03-06 17:05  |  Politics The summit was cut short without an agreement due to differences over the extent of denuclearization and sanctions relief each side could commit to.

The North Korean leader offered to dismantle the Sohae facility during his first summit with Trump in Singapore in June, and again at his third summit with South Korean President Moon Jae-in in September.

Dismantling activity began some time after the Singapore summit and then stopped in August, according to researchers.

"On the launch pad, the rail-mounted transfer building is being reassembled," 38 North, a project of the Stimson Center think tank, said Tuesday. "At the engine test stand, it appears that the engine support structure is being reassembled."

Commercial satellite imagery indicates the rebuilding started sometime between Feb. 16 and March 2, the report said. (Yonhap)