LIMA, May 5 (Reuters) - Peru pledged to review conditions around a major cooper mine but said it will not lift by Friday an emergency declaration temporarily suspending civil liberties in the area, a step demanded by indigenous protesters camped out at the mine, forcing its closure.

According to a letter on Thursday from the presidency's council of ministers addressed to two local indigenous leaders, the government will only commit to announce findings of a review of conditions around the shuttered Las Bambas mine on Saturday ahead of any possible change to the emergency declaration.

Reuters obtained a copy of the letter, signed by Prime Minister Anibal Torres.

Las Bambas alone is responsible for about 2% of global copper output, and a major source of government revenue in Peru, the world's second-biggest producer of the red metal.

The government has tried unsuccessfully to remove the protesters. Leaders of the local Fuerabamba and Huancuire communities have demanded that possible Saturday talks over their protest can only take place if the emergency order, which suspended the right to assemble and protest, is lifted by the end of Friday.

Huancuire community spokesman Alexander Anglas Quiroz stressed the precondition in a phone interview on Thursday.

The two protesting communities argue the mine has not fully honored its past commitments.

Peru's government declared the state of emergency on April 27, about two weeks after anti-mine protesters from the communities camped out on the property of the mine, which is owned by China's MMG Ltd. (Reporting by Marco Aquino; Writing by David Alire Garcia; Editing by David Gregorio)