(Adds weakening of naira at official FX window)
LAGOS, Nov 20 (Reuters) - Nigeria's naira closed at a new low on Thursday, falling 1.25 percent despite intervention by the central bank, which weakened the currency at its official foreign exchange window.
The central bank unexpectedly sold dollars at 158.41 naira at the window, having earlier auctioned the greenback at 156.59 naira, unnerving dealers worried about the risk of a possible devaluation.
That left dollar orders unfilled from importers who had placed exchange rate limits on their transactions, boosting demand on the interbank market.
The naira closed at a new low of 176.10 to the dollar.
The fall in the currency accelerated the rate of sell-off in the stock market, down 2.1 percent on Thursday as foreign investors who have pulled out more than 670 billion naira in the first ten months of the year continued to sell equities.
Dealers said the central bank stepped up interbank dollar sales, selling close to $250 million which failed to quench demand for dollars, mostly from importers.
Nigeria imports around 80 percent of what it consumes. (Reporting by Chijioke Ohuocha; Editing by Bate Felix and John Stonestreet)