China's Minmetals has submitted a first-round bid for Glencore-Xstrata's $5.9 billion Las Bambas copper mine in Peru, Gu Liangmin, managing director of the state-owned metals and mining company, said on Thursday.

"We have come to the first round of bids for Las Bambas. I can assure that Minmetals is very realistic and all our actions should be rational and not too aggressive," Gu said at the Metal Bulletin copper concentrates conference in London.

"We will be very cautious about our decision. It's unnecessary for Minmetals to buy assets at a crazy price or a price that we believe is not worth it."

Glencore-Xstrata agreed to sell Las Bambas this year to meet demands from China's antitrust authorities after Glencore's takeover of mining group Xstrata. The regulator feared the tie-up handed the newly formed commodities powerhouse too much clout in copper.

Chinalco Mining Corp and Jiangxi Copper are among the Chinese groups also interested in the project, sources familiar with the bid have said. One of the sources said Jiangxi, China's largest copper producer, had paired up with Chinalco.

Peru's Mines Minister Jorge Merino said on Thursday that firms from several different countries have expressed interest in buying Las Bambas.

"I cannot give names of companies," Merino told reporters. "But what I can say is that there are companies from many countries - from Australia, from China, Canadian companies, there are also American companies interested in the project."