(ShareCast News) - South Africa-backed Steinhoff International has upped its stake in France-focused electronics retailer Darty at 160p and offered to buy other shareholders' stock at the same price as it battles long-running French suitor Fnac.Since Thursday, when it first made an offer for Darty at 160p, Steinhoff said it had increased its holding to 108m Darty shares, representing 20.4% of the total, as it looks to wrap up the deal and merge the London-owned retailer with its own Conforama furniture chain.Paris-headquartered Fnac, after on Thursday morning hiking its offer to 145p before later turning the dial up to 153p, said on Friday that after Steinhoff's actions it was "currently considering its position and urges Darty's shareholders to take no action".This followed Wednesday's purchase by Steinhoff International of a 19.5% stake in Darty at 138p per share, an increase from its original 125p offer for Darty last month, when it gatecrashed Fnac's bid, which had been stuck in the mire of the European Union regulatory clearance process since an offer was agreed in November.Fnac had then offered one share for every 37 of Darty's, or a small partial cash alternative, which was originally worth around £558m but has improved as FNAC's shares have risen.Backed by South African retail billionaire Christo Wiese, Steinhoff would seem to deep enough pockets to take Fnac to the brink, although it recently backed out of a bid battle with Sainsbury's for Home Retail.