Twenty-one Indians have been detained in the Shenzhen region of China for alleged diamond smuggling.
The detentions were made on Friday last and the Chinese authorities are moving to press charges of diamond smuggling against them, sources said.
The Indian Embassy in Beijing immediately took up the matter with the Chinese government and sought Consular access to them, they said.
The Consular access has been granted for Wednesday.
In New Delhi, Foreign Secretary Nirupama Rao said a report has been sought from the Embassy in Beijing.
"I am aware that some Indians have been taken into custody by the Chinese authorities in Shenzhen. I have asked our ambassador in Beijing for factual report on this matter," she said.
Rao said Ambassador S Jaishankar "is in touch with the Indian Consular General in Guangzhou, which covers Shenzhen and we are awaiting the full facts from the Ambassador."
In a statement, the Ministry of External Affairs said, "It is aware of the detention of 21 Indian nationals by the Anti-Smuggling Bureau of Shenzhen Customs (China) on 8 January 2010".
"They are charged with illegal transportation of diamonds from Hong Kong to Shenzhen. On learning of this detention, our Embassy in Beijing immediately approached the Chinese authorities seeking consular access to the Indian nationals, as provided for, in a Memorandum of Understanding (MoU) on consular matters of 2003," it said.
"Indian Consular Officers are expected to be granted access to the detained Indian nationals on Wednesday morning, 13 January 2010," the statement added.
According to the local media reports, Chinese authorities have detained 50 people, including 33 foreigners, who were allegedly part of a smuggling ring busted by Shenzhen Customs officials on Friday.
The ring sourced diamonds in Hong Kong and hired Indians and local carriers to smuggle them into Shenzhen before distributing them to factories, which, in turn, sold them in the open market, Shenzhen Daily said.
However, the daily did not specify the number of Indians detained.