WASHINGTON (Yonhap) -- A new building apparently designed to assemble large rockets at North Korea's launch site is similar to the one at Iran's launch complex, a U.S. institute's Web site reported Wednesday, in what could be the latest sign of bilateral missile cooperation.

North Korea began to upgrade its Musudan-ri site in the country's northeast to support future launches of larger rockets, liquid-fueled space launch vehicles or intercontinental missiles, said 38 North, a project of the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies dedicated to analysis of the North.

A new launch pad is under construction at the site and much of the nearby village of Taepodong has been razed to clear the way for what appears to be a new building designed to assemble larger rockets, it said.

"The new facility is somewhat similar to a recently completed horizontal assembly building at Iran's Semnan launch complex, also intended to handle a new large liquid-fueled rocket," 38 North said.

The North Korean facility seems to have a similar layout, with labs and what appear to be administrative offices on the sides of a high bay building. There are also clear differences, however. For example, a T-shaped building at the end of the North Korean structure is not present in Iran, according to the Web site.

The two countries have a long history of missile cooperation, although it is too soon to tell whether that cooperation extends to the design and construction of this facility or the new long-range liquid-fueled rocket, said 38 North.

In 2006, Iran's military commander publicly acknowledged that his country had obtained Scud-B and Scud-C missiles from North Korea during the 1980-1988 Iran-Iraq war, but said it no longer needed Pyongyang's assistance.