North Korean leader Kim Jong Un and US President Donald Trump agreed on "complete denuclearization" of the Korean Peninsula at their meeting two weeks ago.

Recent satellite images of a major nuclear plant in North Korea, however, suggest the country is still upgrading its nuclear facilities, according to analysis by the website 38 North.

The Yongbyon Nuclear Scientific Research Center houses reactors for the production of plutonium, which has civilian and military uses.

Experts have said the improvements don't necessarily mean North Korea is cheating on the deal, and the deal as written lacks specifics regardless.

As such, preplanned improvements like this are expected to take place in the meantime.

Satellite imagery suggests North Korea has continued upgrading its infrastructure at a major nuclear plant in the weeks since Kim Jong Un promised President Donald Trump "complete denuclearization" of the Korean Peninsula.

Images taken by Airbus and seen by 38 North, a website run by North Korea analysts, on Thursday appeared to show that improvements to the Yongbyon Nuclear Scientific Research Center in the country's west were still "continuing at a rapid pace," according to the authors.

The Yongbyon facility is the only known nuclear reactor used for North Korea's weapons program, according to The Guardian.

The site houses reactors for the production of plutonium, which North Korea uses both to fuel its weapons and for experimental light water, which is used mainly to generate electricity for civilian use.

38 North warned that the images alone were not proof that North Korea was going against the denuclearization pledge.

"Continued work at the Yongbyon facility should not be seen as having any relationship to North Korea's pledge to denuclearize," the analysts said.

Take a look at the images below:

The exterior of a cooling water pump house at Yongbyon's 5 megawatt electric, or MWe, plutonium production reactor appears to be complete.

A new channel leading to may be filled with water, the images suggest. It's not clear whether the reactor is being used, however.

Imagery also showed two new buildings near Yongbyon's experimental light water reactor, which experts say is used to generate electricity for civilians and which the country had been continually upgrading over the past few months.

One of them appeared to be a four-story office building for engineers, while the purpose of another nonindustrial-looking smaller building nearby could be a guest house for visiting officials, 38 North said.

Coal bins near the site's thermal plant — where heat could be used to generate steam to drive the nuclear reactor — also appeared in the images to have been depleted since 38 North examined photographs in early May.

It suggests that operations have continued since then, though the experts have not found any other evidence of operations.

The images also showed multiple trucks near the site's radiochemical lab, which further suggests recent activity at the facility.

The experts at 38 North suggested their findings were not unusual.

"The North's nuclear cadre can be expected to proceed with business as usual until specific orders are issued from Pyongyang," they said.

Though Trump celebrated his joint statement with Kim — which promised to "work towards complete denuclearization" on the Korean Peninsula — as a victory, some experts have criticized the lack of specifics on the deal.

The US said earlier this week it would soon provide North Korea with "specific asks" and a "specific timeline" for implementing the agreements from the summit.