* ECB cuts rates, to buy asset-backed securities
* ADP payrolls short of estimates, initial claims up
* Tibco Software gains; to review alternatives
* Ciena stumbles after results, outlook
* Indexes up: Dow 0.38 pct, S&P 0.43 pct, Nasdaq 0.64 pct (Adds comments, data, updates to market open)
By Chuck Mikolajczak
NEW YORK, Sept 4 (Reuters) - U.S. stocks climbed on Thursday after the European Central Bank cut interest rates and announced a new credit plan, and as a flurry of data indicated the U.S. economy was steadily improving.
Both the Dow and S&P 500 touched record intraday highs after the ECB cut interest rates to new lows to fend off deflation and spur stagnating growth in the euro zone, a key trading partner of the United States.
The ECB also said it would begin to buy asset-backed securities to ease credit conditions in the region.
The euro fell as low as $1.2994 against the dollar, dropping below $1.30 for the first time in 14 months.
"The market likes what it heard," said Ken Polcari, director of the NYSE floor division at O'Neil Securities in New York. "At the moment all the uncertainty about (whether the ECB) would do anything is now off the table; they clearly did something and now the market is willing to give it an opportunity."
The Dow Jones industrial average rose 64.41 points or 0.38 percent, to 17,142.69, the S&P 500 gained 8.57 points or 0.43 percent, to 2,009.29 and the Nasdaq Composite added 29.07 points or 0.64 percent, to 4,601.64.
Data showed U.S. initial jobless claims rose to 302,000 last week, within levels consistent with a strengthening labor market, while U.S. companies hired fewer workers than expected in August.
Pointing to sturdy economic growth in the third quarter, a separate report showed the U.S. trade deficit narrowed 0.6 percent in July to its lowest point in six months. Meanwhile, growth in the U.S. services sector picked up to its best in August since 2005, according to the Institute for Supply Management.
Tibco Software rose 4.3 percent to $21.94 after the business software maker said it was reviewing its strategic and financial alternatives as part of a bid to maximize shareholder value.
Ciena Corp shares dropped 7.2 percent to $18.99 after the network equipment company posted third-quarter results and provided its fourth-quarter outlook. (Editing by Bernadette Baum)