UK plasterboard maker BPB has said it will continue to fight a hostile takeover bid from French building materials group Saint-Gobain.
BPB has supplied materials for Malaysia's Petronas Towers
The comments came as Saint-Gobain said it was extending the deadline on its £3.6bn ($5.5bn) offer until 30 October.
The French group said it had received interest from less than 1% of BPB's shareholders at the close of the first day of its takeover offer.
BPB said the 720 pence a share bid "fundamentally undervalued" the firm.
In a statement to the London Stock Exchange, BPB advised shareholders to "continue to reject Saint-Gobain's offer and not complete any form of acceptance".
Analysts believe Saint-Gobain, which owns the UK's Jewson building materials chain, will have to raise its offer for BPB if it wants to take control of the world's biggest plasterboard maker.
BPB shares were unchanged at 739.5 pence in Monday trading.