LONDON (AP) - US private equity firm JC Flowers will not increase its $6.9 billion bid for Friends Provident plc. and warned the British insurer it plans to walk away if talks do not begin by Friday.

Shares in Friends, which rejected the £1.50 ($2.98) per share approach from Flowers last month, dropped almost 10 percent after the US firm's statement.

"Despite several attempts by JC Flowers to engage the board of Friends Provident in discussions over several months, Friends Provident has not been willing to do so," Flowers said in a brief statement Monday to the London Stock Exchange.

Friends said last month that the current proposal, the third from Flowers, "significantly undervalues" its business and refused to negotiate around that figure. Flowers has built up a 2.7 percent stake in the British company.

Friends has said that it will instead continue to focus on its recently announced strategic overhaul.