US STOCKS-Wall St cuts gains; late afternoon selling hits Nasdaq
* Costco, Staples shares slide after results
* Nasdaq underperforms broader market
* Obama to Congress: Back IMF capacity to lend to Ukraine
* U.S. jobless claims at three-month low
* Dow up 0.4 pct; S&P 500 up 0.2 pct; Nasdaq down 0.2 pct
By Angela Moon
NEW YORK, March 6 (Reuters) - U.S. stocks mostly rose on Thursday, but were off session highs as late afternoon selling pushed the Nasdaq into negative territory.
The Nasdaq 100 was down 0.2 percent, led lower by Staples, which lost 15 percent to $11.39 after the largest U.S. office supplies retailer forecast a decline in sales. Staples also said it would close up to 225 stores in the United States and Canada by 2015.
In a boost to riskier assets, the euro hit its highest level against the U.S. dollar since late December after the European Central Bank kept interest rates on hold. Continuación...