Foreign Ministry Spokesman Liu Weimin on Thursday urged countries to take tangible measures to guarantee the security of overseas Chinese people and institutions.

"Although the abduction of Chinese workers by Sudanese anti-government forces was an isolated incident, it harmed their physical and mental health and caused wicked effects," Liu told a regular press conference.

China firmly opposed the abduction, Liu said, noting that the abduction of civilians for political purposes is condemned by the international community as a whole.

Chinese enterprises have made positive contributions to the economic and social development of African countries and benefited their people in recent years, said the spokesman.

A camp of a Chinese company operating at a road construction site near Sudan's Al-Abbasiya Tagali town in the volatile South Kordofan state was attacked by a group of gunmen belonging to the Sudan People's Liberation Movement north sector on Jan. 28.

In the camp at the time were a total of 47 Chinese, 29 of whom were abducted by the assailants while the other 18 managed to flee. Among the latter, 17 were later found by the Sudanese army and transferred to a safe place, and one was confirmed dead after having been missing for days.

The 29 workers were released on Tuesday and arrived in Beijing on Thursday afternoon.