Prominent Azerbaijani rights activist Leyla Yunus, who is being held on treason charges, has been beaten in prison, her lawyer said on Wednesday, AFP reported.

Yunus, a fierce critic of the oil-rich country's poor rights record, "was beaten in a pre-trial detention centre", her lawyer Khalid Bagirov told AFP.

"She was punched and pulled by the hair" by a prison guard, he said.

Azerbaijan's Justice Ministry denied the claims.

"The conditions of Leyla Yunus's detention ensure full respect of human dignity," the ministry press office said.

Yunus, 58, and her husband Arif were arrested in late July and early August respectively, and accused of spying for arch-enemy Armenia. They were placed in pre-trial detention for an initial period of three months.

Yunus heads one of the ex-Soviet republic's leading rights groups, the Institute for Peace and Democracy in Baku.

She has won several international prizes for her work, and has collaborated with Armenian activists advocating the reconciliation of the two countries, which have been locked in a decades-long conflict over the disputed Nagorny Karabakh region.

Bakudaily.Az