LONDON (Reuters) - British Airways-owner IAG's (>> International Consolidated Airlns Grp SA) takeover of Aer Lingus (>> Aer Lingus Group Plc) moved closer to its conclusion on Thursday when the U.S. regulator gave its approval and the Irish carrier's shareholders backed special resolutions linked to the deal.

Investors in Aer Lingus now have until 1600 GMT to accept IAG's 1.3-billion-euro (907 million pounds) offer under an initial deadline.

IAG has already won the backing of the two biggest Aer Lingus shareholders, the Irish government and Ryanair (>> Ryanair Holdings plc), and must wait to see whether shareholder acceptance meets the 90-percent threshold level, which will spell the conclusion of the eight-month takeover process.

European competition officials approved the takeover on Tuesday.

(Reporting by Sarah Young; Editing by Pravin Char)