BEIJING - The All-China Journalists Association has urged local authorities to convincingly explain the controversial detention of a journalist who had reported on "financial problems" at a leading engineering company.

The New Express, a newspaper based in the southern city of Guangzhou, published a front-page plea for the second day on Thursday for police to free its journalist, Chen Yongzhou.

"We hope that related authorities in Hunan will present a convincing and justice-based explanation (on the matter)," the association said Thursday in a statement.

Chen was detained on Saturday in Guangzhou by Changsha police on "suspicion of damaging business reputation" after he reported "financial problems" at Zoomlion, a large engineering company based in Changsha, capital of central China's Hunan Province.

According to a source with the Changsha municipal public security bureau on Wednesday, the newspaper and Chen allegedly "fabricated facts and printed 18 negative reports about Zoomlion without a field survey and verification process."

Of the 18 reports, 14 were written by Chen. The articles were written between September 26, 2012 and August 8 of this year.

The New Express denied Zoomlion's accusation, saying Chen's reports were objective.

"We did not discover Chen did anything that was against professional ethics and laws," said a senior executive on condition of anonymity.

According to the Changsha police bureau, it approved the criminal detention of Chen on Saturday in accordance with the law.

The association said it would continue to keep track of the detention of the journalist.