NEW YORK, Dec 22 - U.S. shoppers took advantage of drastic price cuts this weekend, but even markdowns of 60 percent to 70 percent could not entice those who had already completed their holiday gift buying, according to a survey released on Monday.

"People that went out and shopped spent more money than planned," said Britt Beemer, founder and chief executive officer of America's Research Group, which conducted the survey, including questions posed by Reuters.

"The consumers who said they were done basically didn't do much shopping this weekend despite the deals," he added.

U.S. retailers are facing what could be the worst holiday shopping season in nearly four decades as a year-long recession, tighter credit and mounting job losses squeeze household budgets.

Retailers extended store hours and slashed prices last weekend, often at the expense of their own profits, trying to lure procrastinating shoppers and salvage holiday sales.

But winter storms hit much of the United States Friday through Sunday, disrupting holiday shopping during the crucial last weekend of sales before Christmas.

"It basically took what was already a horrid situation for the retailers and compounded it times ten," said Patricia Edwards, a retail consultant at Storehouse Partners, of the weather that included blizzards and freezing rain.

Beemer said retailers finally gave customers what they wanted, with price cuts as deep as 60 percent to 70 percent. But he still expects holiday sales to drop by 2.8 percent, which would mark the first decline in sales in almost a quarter century of holiday spending surveys.

The International Council of Shopping Centers expects November and December sales at stores open at least a year to fall as much as 1 percent, the largest drop since at least 1969, when the trade group began tracking such data.

Shares tracked by the Standard & Poor's Retail Index .RLX> fell 4.2 percent on Monday, sinking further than the wider market. Top retail declines included department store operators Dillard's Inc, which fell 8.2 percent, and Macy's, which tumbled more than 11 percent.

SUPER SATURDAY PUSH

"Super Saturday," the last Saturday before Christmas, usually ranks just behind "Black Friday" -- the day after the U.S. Thanksgiving holiday -- as the single-largest holiday sales day. Black Friday fell on Nov. 28 this year.

Since the Black Friday weekend sales rush, retailers have been trying to entice reticent shoppers by rolling out increasingly aggressive price cuts. Online retailers have also been extending shipping offers to subsidize purchases made on their websites.

Online shoppers have spent $24.03 billion from Nov. 1 through Dec. 19, down 1 percent from a year earlier, according to comScore Inc.

In a research note on Monday, Wedbush Morgan Securities said aggressive discounts are driving higher customer traffic, but full-priced merchandise is going largely unsold. That means retailers' profit margins will take a hit.

"After the holiday merchandise is gone, we expect retailers to have an extremely difficult time driving traffic in January and February, which could make for more lackluster results for both retailers and their vendors," the note said.

Beemer's survey found that 32.9 percent of shoppers polled this weekend said they spent less than planned, while 32 percent said they spent more than planned.

That was a reversal from earlier in the season, when 38 percent said they had been spending less, while 16 percent said they spent more than planned.

"Consumers, I think, spent a little bit more than they planned," he said. "How can you resist 70 percent off?"

But the buying will not be sustained, he said. About 32 percent of respondents planned to shop sales after Christmas, down from a typical response rate of 58 percent.

Part of that decline could be tied to a decrease in shoppers who expect to receive gift cards this year, which they typically use in post-holiday spending sprees, Beemer said.

The survey found that 41.6 percent plan to buy fewer gift cards this year, while only 16.3 percent plan to buy more.

The survey was conducted on Saturday and Sunday and has a margin of error of plus or minus 3.8 percent.