Fortescue said that it had no information that could account for the sharp spike in trading of its shares. Analysts said there was intensified interest in Australia's iron ore sector after Rio Tinto Ltd and BHP Billiton Ltd proposed to joint venture in Western Australia's Pilbara region last weak. This has fuelled speculation that Fortescue will be increasingly targeted by Chinese steel mills as an alternative supplier of the bulk commodity, or even become a takeover target.