Kohlberg Kravis Roberts, the US private equity group, is believed to have tabled a bid worth up to €12.5bn ($16.2bn) for Auna, raising the stakes in the battle for the Spanish telecommunications group.

KKR tabled the bid just a day after a consortium composed of CVC Equity Partners, Apax Partners and Blackstone were preparing to offer €12bn for Auna, Reuters reports.