British supermarket group Morrisons has agreed to an improved takeover offer worth £6.7 billion ($9.3bn) in cash from a consortium led by Softbank-owned Fortress Investment Group, it said on Friday.

The new Fortress offer comprises 270p per Morrisons share plus a 2p a share special dividend, and is aimed at warding off a possible counter offer by US private equity group Clayton, Dubilier & Rice (CD&R).

"[Fortress] remains committed to becoming the new owner of Morrisons and to being a responsible long-term steward of this great British company through the next stage of its evolution," it said. Morrisons said its board had re-confirmed its unanimous recommendation of the offer.

The board of the company that also owns the Nutmeg clothing brand had previously agreed a Fortress offer worth 254p a share or a total of £6.3 billion on July 3. However, major Morrisons investors Silchester, M&G and JO Hambro all indicated that offer was too low.

CD&R had a 230p a share proposal worth £5.52 billion rejected by Morrisons on June 17.

Britain's Takeover Panel, which regulates corporate takeovers, has set an August 9 deadline for CD&R to come back. Shares in Morrisons were up 2.5% at 278.75p by 10:55 GMT - a premium to the latest offer - on hopes that it will.

Shareholders in Morrisons are due to vote on the Fortress bid on August 16.

To pass, the offer needs the support of shareholders representing at least 75% in value of voting investors at the meeting. Analysts have speculated that Amazon, which has a partnership deal with Morrisons, could still enter the fray.