Burmese authorities on Friday said they had made a fresh round of arrests over a spate of protests demanding apologies for a police crackdown on a rally at a Chinese-backed copper mine last month.

Demonstrations have been held across Burma, in a display of public anger for injuries, including severe burns, sustained by dozens of monks in a pre-dawn raid on protest camps at the mine in November.

“Some activists were arrested for questioning,” a police official told AFP, asking not to be named. He said they were picked up in Burma’s second-biggest city Mandalay for protesting without permission.

Activist group All Burma Federation of Student Unions, which took part in street action this week, said eight people were arrested late Thursday.

“Four activists from Mandalay have not been released yet. We do not know where they are,” a representative of the group told AFP on condition of anonymity.

Hundreds of monks, supported by activists, staged demonstrations across Burma Wednesday over the mine crackdown, the toughest clampdown on demonstrators since a reformist government came to power last year.

The wife of Thein Aung Myint, one of the arrested protesters, said her husband was taken from their home in the evening and had not returned.

“I think he was taken because of his involvement in the monk-led protest on December 12,” said Khet Khet Tin.

Last week Religious Affairs Minister Myint Maung apologised to some of the country’s most senior clerics for injuries to about 99 monks, state media said.

About 100 police also apologised to a group of monks in Monywa soon after the crackdown.

Photographs of the protesters’ injuries have stirred outcry in Burma, reminding the public of brutal junta-era security tactics, including the notorious crackdown on mass monk-led rallies in 2007 known as the “Saffron Revolution”.

The dispute at the Monywa mine centres on allegations of mass evictions and environmental damage caused by the project – a joint venture between Chinese firm Wanbao and military-owned Myanmar Economic Holdings.

China insists that the contentious points have already been resolved.

Eight people arrested in connection with earlier protests against the mine in recent weeks were released on bail on Tuesday.