China is strongly dissatisfied with and firmly opposes the signature of the first agreement under the "U.S.-Taiwan Initiative on 21st Century Trade," a spokesperson for the Ministry of Commerce said on Friday.

The comments came after the United States signed the agreement with the Taiwan region of China and sent government officials to attend the ceremony, in disregard of China's repeated solemn representations.

"Taiwan is an inalienable part of China's territory," the spokesperson said.

The spokesperson said that China firmly opposes countries with which it has diplomatic relations conducting any form of official exchange with Taiwan, including the negotiation and signature of economic and trade agreements that have sovereign implications or are official in nature.

"We urge the U.S. side to abide by the one-China principle and the three China-U.S. joint communiques, handle economic and trade relations with Taiwan in a prudent manner, and cease any form of official U.S.-Taiwan exchanges," the spokesperson said.