Dollar Tree Inc. reported a smaller-than-expected rise in quarterly comparable store sales and forecast current-quarter results below estimates.

The company's shares fell 6 percent in premarket trading.

Dollar stores have been battling increased competition from Wal-Mart Stores Inc. and other large discount chains, which are increasingly chasing budget-conscious consumers by offering more items priced at $1 or less.

The company said it expects fourth-quarter earnings of $1.01-$1.07 per share on sales of $2.25 billion-$2.31 billion. It expects comparable-store sales to be in the low-single digit percentage range.

Analysts on average were expecting fourth-quarter earnings of $1.10 per share, on revenue of $2.32 billion, according to Thomson Reuters I/B/E/S.

Dollar Tree reported a 3.1 percent increase in same-store sales in the third quarter ended Nov. 2. But this fell short of analysts' average expectations of a 4.5 percent rise.

The company's results mirrored those of Target Corp., which reported a smaller-than-expected 0.9 percent rise in comparable store sales, blaming what it called "constrained" consumer spending.

Dollar Tree's net income fell to $125.4 million, or 58 cents per share, from $155.4 million, or 68 cents per share, a year ago.

The company said last year's earnings included a one-time gain of 17 cents per share related to the sale of its ownership interest in Ollie's Holdings Inc.

Analysts had expected Dollar Tree to earn 60 cents per share.

Net sales rose 9.5 percent to $1.88 billion, but missed analysts' average expectations of $1.91 billion.

Dollar Tree shares, which have risen 42 percent in one year through Wednesday's close, had closed at $58.92 on the Nasdaq on Wednesday.