Barclays Q3 profit rises 12%, announces $670 million buyback

(Corrects profit to 'up' from 'down' in paragraph 2)

LONDON, Oct 22 (Reuters) - Barclays said its third-quarter profit rose 12% on Thursday, as it reported growing income and stable costs that allowed the bank to announce a new share buyback worth £500 million ($669.85 million).

The British lender reported pretax profit for the July to September period of £2.3 billion, up from £2.1 billion a year ago and just in line with the average of analysts' forecasts of £2.4 billion.

($1 = 0.7464 pounds)

(Reporting by Lawrence White; Editing by Tommy Reggiori Wilkes)