Stocks rallied on Thursday as a regional Federal Reserve survey eased concerns about slowing economic activity, while cell phone makers Motorola and Nokia gave strong earnings outlooks.

The Dow Jones Industrial Average was up 206.24 points, or 2.1 percent, to close at 10,218.60. The Standard & Poor’s 500 Index was up 22.45 points, or 2 percent, to finish at 1,159.95. The Nasdaq Composite Index was up 48.65 points, or 2.5 percent, to close at 1,962.41.

The market extended gains in early afternoon after the Federal Reserve Bank of Philadelphia said its business activity index rose to 25.3 from 11.4 in March, more than double the amount economists had forecast.

In earnings news, Nokia gained 6.6 percent to $16.35 after reporting double-digit growth in the first quarter and raising its earlier estimate of the global mobile handset market in 2005. Its rival Motorola also had better-than-expected results on a solid rise in sales. Motorola was up 6.7 percent at $15.93.

Among local movers, Jamdat Mobile Inc. rose 15.8 percent to close at $18.19 after the L.A.-based wireless interactive game company announced after Wednesday’s closing bell that it acquired Blue Lava Wireless LLC for about $137 million and had raised its first-quarter revenue above its prior outlook. Jamdat said it would report first quarter revenue of $15 million, above its previous forecast of $14.1 million.

And Wilshire Bancorp Inc. gained 4 percent to $14.08 after the L.A.-based parent company of Wilshire State Bank reported net income of $6.1 million (21 cents per diluted share) for the first quarter ended March 31, compared with $4.3 million (15 cents) for the like period a year earlier.

On the down side, Iris International Inc. fell 4.4 percent to close at $14.24 after the Chatsworth-based firm’s stock was downgraded to “hold” from “buy” by analyst Ernest Andberg at Feltl & Co.