China has protested to India over the opening of the Taiwan region's office in the Indian city of Mumbai, urging India to honor its commitment and refrain from engaging in any official interaction with the region.

"The Chinese side has lodged solemn representations to the Indian side," Chinese Foreign Ministry spokeswoman Mao Ning said on Thursday.

Reports said the office, Taiwan's third such office in India, was opened on Wednesday.

China firmly opposes any country it has diplomatic relations with engaging in any form of official contact and exchanges with Taiwan, including mutual establishment of representative institutions, Mao told a regular news conference.

Inalienable part

"There is but one China in the world. Taiwan is an inalienable part of the Chinese territory," Mao said.

Noting that India has made a serious political commitment to follow the one-China principle, Mao said the principle is the political foundation for China-India relations.

"The Chinese side urges the Indian side to strictly adhere to the commitment, handle Taiwan-related issues cautiously and properly, avoid any official exchanges with Taiwan, to prevent disrupting the improvement of China-India ties," the spokeswoman added.