* Services sector grows in April, fastest pace in 8 months
* JPMorgan leads banks lower after trading revenue warning
* Apple shares close above $600 for the first time since Oct. 26, 2012
* Dow up 0.1 pct, S&P up 0.2 pct, Nasdaq up 0.3 pct (Updates close with latest volume, AIG down after the bell)
By Caroline Valetkevitch
NEW YORK, May 5 (Reuters) - U.S. stocks ended slightly higher as data showed strength in the services sector and Apple shares rose above $600 for the first time since late 2012.
Limiting the day's gains, however, were concerns over an escalation of tensions between Ukraine and pro-Russia separatists. Ukrainian forces were ambushed by separatists, triggering heavy fighting on the outskirts of the rebel stronghold of Slaviansk, a day after a Ukrainian police station in Odessa was stormed.
The Institute for Supply Management's services sector index hit the fastest pace in eight months in April, topping expectations. It was the latest report to offer upbeat news on the economy after an unusually harsh winter.
"The ISM services came out and showed pretty good growth, and that obviously brought back some buyers," said Ryan Detrick, senior technical strategist at Schaeffer's Investment Research in Cincinnati, Ohio.
Apple shares, up 1.4 percent at $600.96, led both the S&P 500 and Nasdaq higher. Late in the session, the stock broke above $600, and it closed above the level for the first time since Oct. 26, 2012.
The Dow Jones industrial average rose 17.66 points or 0.11 percent, to 16,530.55, the S&P 500 gained 3.52 points or 0.19 percent, to 1,884.66 and the Nasdaq Composite added 14.158 points or 0.34 percent, to 4,138.055.
Short-term upward trendlines were tested in the S&P 500 and the Dow but not broken, said Adam Sarhan, chief executive of Sarhan Capital in New York, suggesting the uptrend is not over.
Shares of Fannie Mae and Freddie Mac gained after activist investor William Ackman recommended the shares of mortgage finance giants during the Sohn Investment Conference in New York. Fannie was up 3 percent at $4.10 while Freddie was up 6.3 percent at $4.23.
On the downside, shares of JPMorgan Chase fell 2.4 percent to $54.22, the biggest drag on the S&P 500. The bank said late Friday it expects second-quarter revenue from bond and equity trading to decline about 20 percent from a year ago. The S&P financial index fell 0.4 percent.
Pfizer Inc shares fell 2.6 percent to $29.96. The biggest U.S. drugmaker reported revenues well below analysts' expectations.
After the bell, shares of American International Group Inc declined 1.9 percent to $51.70 after it posted a 27 percent fall in quarterly income.
During the regular session, Target Corp shares fell 3.5 percent to $59.87. Chief Executive and Chairman Gregg Steinhafel will leave the No. 3 U.S. retailer in the wake of a data breach last year that hurt profits, shook customer confidence and prompted congressional hearings.
But shares of B/E Aerospace jumped 9.3 percent to $97.22. German aircraft seating maker Recaro said it was studying the possibility of buying B/E Aerospace assets after the U.S. company announced a surprise review.
About 5 billion shares changed hands on U.S. exchanges, well below the 6.7 billion average for the last five sessions, according to data from BATS Global Markets. (Editing by Bernadette Baum and Nick Zieminski)