"Portugal has a unique geostrategic positioning, and belonging to wider cooperation spaces enhances its partnerships. In this complex network of relationships, Macao will continue to play a major role as a bridge to promote long-term friendship" between Lisbon and Beijing, and as a "platform for economic and cultural cooperation with Portuguese-speaking countries", he said.

Regarding Macao's return to the motherland, Costa said the event was "constructive and constituted a historic milestone in the consolidation of the friendship and trusting relationship" between the two countries.

"Since 1999, we have made progress in a relationship of growing mutual trust in areas such as language, education, culture, justice, tourism, trade and investment," the prime minister said.

Foreign Ministry spokesman Geng Shuang said on Thursday that China appreciates the positive statement.

Geng said Portuguese President Marcelo Rebelo de Sousa sent a letter to President Xi Jinping, expressing Portugal's admiration for Macao's economic and social development over the past 20 years as well as the SAR's successful practice of the "one country, two systems" principle.

"They expressed their belief that the China-Portugal relationship will continue to be a unique example of harmonious coexistence between countries with different political systems and cultural traditions," Geng said at a news conference.

He noted that the two countries' proper handling of Macao's return on the basis of good will and mutual trust has set a good example for the international community.