* First quarter organic sales growth 4 pct vs forecast 3 pct
* Swedish lock maker says clear improvement in European market
* Harsh winter weather weighs on Americas business
* Shares rise 1.4 pct (Adds detail, background, quote)
STOCKHOLM, April 29 (Reuters) - Assa Abloy, the world's biggest lock maker, posted stronger than expected first quarter like-for-like sales on Tuesday as business picked up in Europe to offset a weather-related slowdown across the Atlantic.
Assa, which makes locks under brands including Yale and Pan Pan, has seen demand recover up the past quarters, mainly in the United States, but recently also in its biggest market, Europe, where the debt crisis weighed on demand for years.
"The first quarter was characterized by a clear improvement in Europe, helped to some extent by the effect of Easter, but some weakening in the USA, probably due to the very cold weather," Chief Executive Johan Molin said in a statement.
The company, which has racked up dozens of acquisitions in recent years to expand its position in a fragmented industry, said sales excluding acquisitions and currency swings rose 4 percent year on year - above analysts' expectations of 3 percent.
Assa, a rival to U.S. Ingersoll-Rand and Stanley Black & Decker, said organic sales growth in Europe rose to 5 percent from 1 percent in the preceding quarter, outpacing its Americas and Asia/Pacific markets.
Earnings before interest and tax, excluding one-off items, rose to 1.86 billion crowns ($284.3 million), just below a mean forecast of 1.89 billion in a Reuters poll of analysts.
Overall sales rose 13 percent year on year, in line with forecasts.
($1 = 6.5414 Swedish Crowns) (Reporting by Niklas Pollard and Oskar von Bahr; Editing by John Stonestreet)