A total of 22 investigations into coal theft are underway in Mongolia amid protests, with 15 people arrested and 10 detained, the deputy head of the country's Anti-Corruption Committee's investigation department said.

"A total of 22 investigations are underway. During the investigations, 47 searches of facilities have been conducted, 15 people have been arrested and 10 have been detained," News Press quoted him as saying.

He said law enforcement officers are taking statements from witnesses and suspects. The Anti-Corruption Committee set up a working group to expedite the investigation.

For 10 days, a demonstration of several thousand protesters has been taking place in front of the Government Palace in the Mongolian capital of Ulaanbaatar amid reports of a major coal theft. According to various Mongolian media reports, thefts range from $1.8 billion to $13 billion.