March 4 (Reuters) - Struggling retailer RadioShack Corp reported a wider quarterly loss on Tuesday and said it will close up to 1,100 U.S. stores after a huge drop in sales over the holidays, sending the stock down more than 15 percent.

Sales at the Fort Worth, Texas-based chain have been in free fall amid executive departures, tough competition and an image problem. Despite its ubiquitous presence in the United States, analysts say it has not done enough to transform itself into a destination for mobile phone shoppers or become hip enough to woo younger shoppers.

Its net loss widened to $191.4 million, or $1.90 a share, in the fourth quarter, from $63.3 million, or 63 cents, a year earlier.

Sales fell to $935.4 million in the quarter covering the all-important holiday season, from $1.17 billion in the year-ago period. Analysts, on average, looked for sales of $1.12 billion, according to Thomson Reuters I/B/E/S.

Sales at stores open at least a year fell 19 percent on weak customer traffic.

Chief Executive Officer Joe Magnacca, who took the helm in February 2013, has said he expected the turnaround to take several quarters.

The stock fell 15.4 percent to $2.30 in premarket trade.