British brewer SABMiller doubled the group's cost savings target on Friday, ramping up its defences to help fend off a vast takeover bid from AB InBev.

The company said in a statement that it aims to achieve annual savings of at least $1.05 billion (932 million euros) by March 2020. That compared with the previous guidance of $500 million by 2018.

And in a sideswipe at AB InBev, SABMiller added that the latest cost savings plan assumes that "there will be no change in the ownership or control" of the firm.

"Whilst we are already a highly efficient business we are continuing to remove duplication across markets, bringing specialist expertise in areas like procurement under one roof, and standardising common processes," chief executive Alan Clark said in the statement after meeting with investors.

The pledge to double annual cost savings from current targets came a day after Anheuser-Busch InBev, the world's biggest brewer, appealed directly to SABMiller shareholders to merge their two companies.

Belgian-Brazilian titan AB InBev, which produces Budweiser and Stella Artois lagers, made the appeal after failing with its third takeover tilt at the London-listed maker of Foster's and Grolsch.

The improved third bid -- pitched at £42.15 per share in cash and worth £68 billion ($103 billion, 92 billion euros) -- was rejected by the SABMiller board as being too low.

In its investor presentation SABMiller repeated that it believes the AB Inbev offer "very substantially undervalues the company" and pointed out its highly conditional nature, including significant regulatory hurdles in the United States and in China.

In reaction in London deals, SABMiller's share price rallied 0.76 percent to close at 3,668.50 pence.

AB Inbev shares climbed 0.82 percent to finish at 98.30 euros in Brussels.