LIMA, April 20 (Reuters) - Peru will declare a state of emergency near Southern Copper Corp's Cuajone mine, the country's prime minister said on Wednesday, as protests hit top mines in the Andean nation, halting 20% of national copper output.

Peru is the world's No. 2 producer of the red metal. Impoverished communities in Peru's copper-rich Andes have been staging growing protests against mining companies including Cuajone, MMG Ltd's Las Bambas and Glencore's Antapaccay.

They complain that the mineral wealth has not trickled down to their communities despite high international prices.

Cuajone suspended operations on Feb. 28 after residents of a nearby community shut down water supply to the mine, demanding financial compensation and a share of future profits.

The government of President Pedro Castillo had been reluctant to use emergency declarations, which suspend civil liberties, in order to suppress protests against Peru's mighty copper industry.

But Prime Minister Anibal Torres on Wednesday said the government was running out of patience to solve the issue.

Communities "are demanding something irrational, $5 billion," Torres said. "That has led us to declare a state of emergency, and the problem has to be solved now."

Reuters could not reach community representatives for comment.

In addition to Cuajone, production at Las Bambas stopped on Wednesday, after residents of the Fuerabamba community entered the mine and set up camp inside of it, leading the Chinese-owned mine to announce a suspension of operations.

Peruvian government officials are holding a meeting with Fuerabamba representatives to try to diffuse the situation but had yet to reach a resolution as of Wednesday evening.

Castillo was elected last year with massive support of communities in mining regions amid pledges to better distribute copper profits.

Peru produced 2.3 million tonnes of the red metal in 2021, according to government statistics. Las Bambas produced close to 300,000 tonnes while Cuajone produced another 170,000 tonnes, totaling 20% of national copper production.

Also on Wednesday, protests started against a planned expansion at Glencore-owned Antapaccay. A source close to the company said the demonstrations had not blocked a key transport road shared by Antapaccay, Las Bambas and Hudbay's Constancia copper mine.

(Reporting by Marcelo Rochabrun; Editing by Aurora Ellis)