North Korea and China have signed an agreement to build a new bridge over the Tumen River that runs between the two nations, Chinese officials said on Wednesday, in the latest sign that economic ties between Pyongyang and Beijing remain largely unaffected despite the North's nuclear and missile programs.

The agreement was signed in Pyongyang on Tuesday by North Korean Deputy Foreign Minister Pak Myong-guk and the Chinese Ambassador to North Korea, Li Jinjun, the Chinese Embassy said in a statement.

The new bridge will link the North Korean border city of Nanyang and the Chinese border city of Tumen, where bilateral trade with North Korea is bustling.

Financial terms of the deal were not disclosed.

During the signing ceremony, Li told Pak that the new bridge "will provide greater convenience for people of the two countries and trade ties" and "will also contribute to improving infrastructure of the China-North Korean border," according to the statement.

Pak said, "North Korea is willing to maintain close communication and coordination with China, make every effort to ensure the smooth progress and complete construction of the bridge as soon as possible."

The agreement was signed on the day when North Korea confirmed that it has restarted operations at its main nuclear reactor, saying that Pyongyang was working to advance its nuclear weapons "in quality and quantity."

Satellite images of North Korea's Yongbyon nuclear facility have shown activities of expanding plutonium production, but it was the first time that Pyongyang has confirmed that it resumed operations of the five-megawatt reactor, which is considered as the North's main source of weapons-grade plutonium. (Yonhap)