Beer giant SABMiller turned up the heat in its takeover battle with rival Anheuser-Busch InBev as it said a sweetened bid from the Budweiser brewer "substantially undervalues" the business.
AB InBev said it had tabled a third proposal of £42.15 per share for Peroni and Grolsch owner SABMiller after two previous bids of £38 and £40 were rejected.
AB InBev's latest approach values SABMiller at around £68bn, which would make it the biggest takeover of a British company.
SABMiller chairman Jan du Plessis gave a cool response to AB InBev's advances, saying his firm is the "crown jewel of the global brewing industry".
He added: "AB InBev needs SABMiller, but has made opportunistic and highly conditional proposals, elements of which have been deliberately designed to be unattractive to many of our shareholders.
"AB InBev is very substantially undervaluing SABMiller."
AB InBev is the world's biggest beer business, while SABMiller is the global number two.
SABMiller said in a statement that in an October 5 meeting with AB InBev, the Belgium-based firm tabled a second bid of £40 a share and indicated it would raise its offer to £42, subject to a recommendation by the board and other conditions.
The SABMiller board met later that day and rejected the £40 proposal, and said if the offer was raised to £42 it would also reject that bid because it still undervalued the business.
The FTSE 100 firm added that this new offer "is only 15p higher than the £42 proposal considered and rejected on October 5 2015".
However, SABMiller said its board would meet to formally consider AB InBev's latest proposal as soon as practicable before making an announcement.
AB InBev said it was "disappointed" that SABMiller had rejected its prior approaches "without any meaningful engagement".
But it added: "AB InBev believes that this revised proposal should be highly attractive to SABMiller shareholders and provides an extremely compelling opportunity for them."
AB inBev said its latest offer represented a premium of around 44% to SABMiller's closing share price.
Chief executive Carlos Brito said: "Put simply, we believe we can achieve more together than each of us could separately, bringing more beers to more people and enhancing value for all of our stakeholders."
SABMiller's largest shareholder, Altria Group, has come out in support of the latest offer, claiming the deal would create "significant value" for all SABMiller shareholders.
It said: "Altria urges SABMiller's board to engage promptly and constructively with AB InBev to agree on the terms of a recommended offer."
The blockbuster deal, if accepted, would create a drinks giant worth more than £180bn.
Shares in SABMiller have rocketed since AB InBev's takeover hopes were revealed on September 16.
SABMiller toasted a strong summer for beer sales on Tuesday despite a "material" currency hit.
Surging demand in emerging markets such as Africa and Latin America helped underlying net revenues lift 6% and sales by volume by 2% over the three months to the end of September.
Good weather also saw net revenues rise 3% across Europe in the quarter, with its Peroni brand remaining popular in the UK, although sales in the region remained flat overall in the first half and interim sales by volume fell 3%.
SABMiller revealed that the strong US dollar took its toll on reported results, with net revenues down by 9% in the second quarter and half-year as a whole.
AB InBev has a stable of more than 200 beers, including Corona, Beck's, Leffe and Hoegaarden.
SABMiller also has Miller, Foster's, Coors and Bulmers cider. It employs around 69,000 people in more than 80 countries and has global annual sales of more than US$26bn.
Its suitor AB InBev, based in Leuven, Belgium, has a 155,000-strong global workforce and makes more than US$47.1bn in global revenues.
SAB attempted to acquire Heineken a year ago but its advances were rebuffed.