The Nasdaq Stock Market ( NDAQ) and the London Stock Exchange are yelling at each other again. Nasdaq is using stronger language to prod LSE shareholders toward accepting its $5.3 billion hostile bid. But the LSE is standing its ground. Nasdaq said Monday that by remaining independent, the London exchange "fails to acknowledge growing customer dissatisfaction, new competitive threats introduced by upcoming regulatory changes or accelerating consolidation of the exchange landscape." A "key issue is how LSE will react to the substantial future challenges that it will face in 2007 and beyond," Nasdaq said in a press release Monday ahead of a procedural deadline Thursday. "We believe the LSE is unprepared for those challenges ahead." For now, the LSE doesn't seem to be quaking in its boots. "Exchange shareholders should not be persuaded into selling their shares well below their true value by Nasdaq's bluster," CEO Clara Furse said in a statement. Nasdaq is under increasing pressure to get the London deal done as the exchange sector continues to consolidate. The New York Stock Exchange ( NYX) is set to close on its $14 billion acquisition for Europe's Euronext exchange. The tech-heavy electronic exchange was responding to the LSE's formal rejection last month of its so-called final offer. Nasdaq had made the bid in late November, saying at the time it was willing to pay 1,243 pence per share for the London bourse.