NEW YORK — Nordstrom’s shares tumbled in extended trading Thursday after the upscale department store slashed its annual sales and profit outlook.

The Seattle-based chain reported that its first-quarter earnings dropped 64 percent as a key sales measure – sales at stores opened at least a year – declined for the first time in almost seven years.

Nordstrom said that it had to mark down merchandise more aggressively to clear out inventory, eating into profit margins.

Nordstrom earned $46 million, or 26 cents per share, for the quarter ended April 30. That compares with $128 million, or 66 cents per share, last year.

Sales rose 1 percent to $3.25 billion, including credit card revenue. But the key revenue measure was down 1.7 percent, marking the first drop since third quarter of 2009 when that measure was down 1.2 percent.Analysts had forecast earnings per share of 47 cents on revenue of $3.29 billion.

Nordstrom now expects full-year earnings in the range of $2.50 to $2.70 per share. It had forecast earnings between $3.10 and $3.35 a share.

It expects that this year its sales at stores opened at least a year will range from a decline of 1 percent to an increase of 1 percent.

Its stock fell 17 percent, or $7.65 per share, to $37.58 in after-hours trading Thursday.