* At least 12 killed in wave of attacks since crackdown
* Both opposition and junta backers hit
* Libyan mediation offer rejected
(Adds further details, Libyan mediation offer rejected)
By Saliou Samb
CONAKRY, Oct 23 At least a dozen people have been murdered in Guinea over the past month, with some of the attacks suspected to be revenge killings after last month's bloody government crackdown on protesters.
The attacks by unknown assailants come amid increasing international condemnation of Captain Moussa Dadis Camara's ruling military junta after gunmen opened fire on unarmed demonstrators in a stadium on Sept 28.
"We have counted 12 assassinations since Sept. 28. This does not include the killing of a top official in the youth ministry," a police source told Reuters on Friday of the killing by an armed gang earlier this week of Amadou Sadio Diallo, seen as a supporter of Camara.
The police source added that the majority of the attacks in and around the capital Conakry since Sept. 28 have been committed by bandits, but added without elaborating that the rest appeared to be a "settling of scores".
"Both the opposition and those in power have been hit."
Separately, Guinean opposition leaders on Friday rejected an offer of mediation by Libya put forward by Tripoli's ambassador in the capital Conakry. Libyan leader Muammar Gaddafi has been one of the few voices abroad expressing support for Camara.
Some 157 people who had gathered to demand Camara opt out of elections set for January were killed in the crackdown and more than a thousand others were injured, according to a local human rights group.
One police source said investigators suspect "death squads" are deliberately spreading fear in the country, the world's top bauxite supplier.
Guinea, whose mineral riches have drawn large investments from international companies like Rio Tinto, Alcoa and RUSAL, has become increasingly isolated from the international community since Camara took power in a coup last December.
West Africa regional bloc ECOWAS imposed an arms embargo last Saturday against Guinea, accusing the ruling military junta of "mass human rights violations".
The United States, France and the European Union have called on Camara, who seized power in a coup last December, to resign and the International Criminal Court said last week it was investigating the Sept. 28 killings and abuses including rape. (Reporting by Saliou Samb; Writing by Richard Valdmanis)