In what could prove another twist in the Endesa takeover saga, energy and construction firm Acciona has begun building up its stake in the Spanish utility.

Acciona has acquired 10% of the share capital in Endesa at E32 per share, and said that it is not ruling out the possibility of increasing its stake up to a percentage that would not require launching a takeover bid. This would mean raising its stake in Endesa to 25%.

Acciona said that the E3.4 billion acquisition of the 10% reference stake in Endesa supports the company’s growth strategy in the energy sector. Acciona also operates in a number of other markets, including transport, construction and real estate. However, some industry onlookers have interpreted the move as the latest bid by the Spanish government to block E.ON’s proposed takeover of Endesa.

Acciona Energia operates in the renewable energy sector and has a total installed capacity of 2,800MW as of June 2006. Endesa, which is currently in the midst of a takeover tussle between E.ON and Gas Natural, aims to reach 3,000MW of renewable energy capacity in 2009.