US STOCKS-Wall St dips amid overseas concerns; energy weakens
* Investors watching situations in Greece, Ukraine
* S&P 500 coming off record closing high
* Celsus shares plummet after drug fails study
* Dow, S&P 500 and Nasdaq all fall 0.3 pct (Updates to the open of U.S. trading)
By Ryan Vlastelica
NEW YORK, Feb 17 (Reuters) - U.S. stocks edged lower on Tuesday, with the S&P 500 pulling back from record levels as investors continued to grapple with the uncertainty over a Greek debt deal and a fragile Ukraine truce.
Equities have been in an uptrend lately, with major indexes notching a second week of solid gains last week. Much of the advance came on signs of progress for the debt deal in Greece, as well as reduced tension between Russia and Ukraine.
Both situations appeared less stable over the long weekend when U.S. stock markets were closed Monday for Presidents Day. European Union finance ministers pressured Greece to remain in an international financial rescue program after talks collapsed on Monday. U.S.-listed shares of the National Bank of Greece fell 12 percent to $1.41.
"This has been a well-advertised point of confusion, so it isn't taking the market by surprise," said Liam Dalton, president of Axiom Capital Management in New York. Continuación...