HSBC, the giant international banking group, is backing Randgold Resources' $1.5 billion bid for gold mining group Ashanti, cranking up the pressure on

AngloGold, which tabled a lower $1.1bn rival offer this summer. Ashanti, headed by Sam Jonah, meets to study both bids at a special board meeting at its headquarters in Accra, Ghana, on Tuesday.

AngloGold, in which Anglo American, the London-based multinational, holds a 51 per cent stake, may have to improve its terms, or risk losing Ashanti to the much smaller Randgold, headed by Mark Bristow, the swashbuckling South African businessmen who has built up the firm over the last 20 years.

AngloGold had argued that Randgold did not have the financial back-up to develop Ashanti's deep mines, centred around its flagship Obuasi mining operation.

But according to banking sources in London, HSBC, together with four other banks, including Germany's HVB, are making available a ?250m revolving credit facility that Randgold can draw down over a five-year period.

Randgold is hoping that Ashanti may recommend its bid over AngloGold this week. But analysts argue that the Ghanaians could stick with AngloGold as it has more financial resources to expand Ashanti's operations away from its African heartland. Ashanti backed AngloGold when it was the only bid on the table, but its position now is unclear.

Observers suspect that the Ghanaians may be playing off the two firms to maximise the value for what is viewed in Accra as the country's most valuable national asset.

The government of Ghana, which owns 16.9 per cent of Ashanti and has a 'golden share', must approve the deal. Soci?t? G?n?rale, Accra's appointed advisers, are due to report back to ministers at the end of this month.

AngloGold needs a commercial victory after last year's setback, when it lost out in a bid to acquire Normandy, Australia's largest gold producer. Taking over Ashanti would make it the world's biggest gold producer once more. Randgold is keen to propel itself into the big league, and cannot be written off as it is well respected in Africa, but questions remain whether it has either the resources or the technical expertise to fully develop Ashanti's mines.

Another player in the bid battle is London-based mining group Lonmin, which owns a 28 per cent stake in Ashanti and had given its backing to AngloGold's bid before Randgold arrived on the scene. But Lonmin, which was created out of the late Tiny Rowland's international mining interests, has now adopted a wait-and-see position.