NEW YORK (Reuters) - Top US retail chains posted a record rise in monthly same-store sales in March, helped by an early Easter holiday and an improving job market, in the strongest sign yet of revived consumer demand.

Sales at stores open at least a year rose 9.1 percent in March, the largest monthly jump since Thomson Reuters began tracking results in 2000 and ahead of Wall Street estimates of a 6.3 percent increase. More than 90 percent of 28 retailers tracked beat expectations.

Executives at retailers from department store operator Macy's to discounter Target Corp warned that the huge jump in March would come at the expense of April sales.

But analysts and economists took a brighter view of the two-month period, saying underlying consumer spending was accelerating.

"Even if you take out Easter, you still saw a better month this month than you did in February and January," said Doug Conn, credit analyst and managing director at Hexagon Securities. "There's something going on besides Easter, in other words."

Michael Niemira, chief economist at the International Council of Shopping Centers, said same-store sales had risen nine percent in March by his tally, and he predicted April would be flat to down three percent.

"I think we are seeing that sustained pick-up," he said. "It won't be nine percent. It may be four percent."

Retail shares tracked by the Standard & Poor's Retail Index rose 0.9 percent yesterday, compared with a 0.3 percent decline for the wider S&P 500 Index.

Department stores showed the biggest gains in March, with a 12.3 percent increase, but also said April results would be far more modest.

Macy's said same-store sales rose 10.8 percent in March from a year earlier, well ahead of the 7.9 percent increase analysts had expected, but it forecast flat results for April.

Rival chain Kohl's forecast a low double-digit percentage same-store sales decline following its 22.5 percent surge in March.

Other retailers sounded similar warnings. TJX Cos Inc said same-store sales were up 12 percent, far above estimates, prompting the off-price retailer to raise its profit outlook. But it sees much more modest same-store sales growth of two percent to four percent in April.

Kohl's shares fell 0.5 percent, while Macy's was up 1.1 percent. Morning gainers also included Target, up 2.4 percent after it said earnings would come in ahead of Wall Street forecasts , and Gap Inc, which rose 3.5 percent after reporting a monthly sales growth rate that was more than double the average forecast.