* EMC jumps on report of activist investor stake
* Futures down: Dow 42 pts, S&P 5 pts, Nasdaq 5 pts
NEW YORK, July 21 (Reuters) - U.S. stock index futures edged lower on Monday as developments in Ukraine and Middle East looked to dominate trading amid a thin economic calendar.
* The death toll from the two-week conflict topped 500 amid growing international calls for a ceasefire, and Israeli jets, tanks and artillery continued to pound the Gaza Strip. Fighters from Hamas, which controls Gaza, have repeatedly tried to infiltrate Israel over the past week through a network of hidden tunnels.
* Ukraine launched a military assault to break a rebel hold on the eastern city of Donetsk in the first major fighting in the area since a Malaysia Airlines jet with 298 people aboard was shot down last week. The United States and its allies have pointed the finger at pro-Russian rebels and at Moscow itself over the downing of the plane. Russia has denied involvement and blamed the Ukrainian military for the disaster.
* The United States and the EU last week announced further economic sanctions against Russian interests, which could become more stringent following the crash.
* S&P 500 e-mini futures were down 5 points and fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract, indicated a lower open. Dow Jones industrial average e-mini futures fell 42 points, and Nasdaq 100 e-mini futures lost 5 points.
* The economic calendar included the Chicago Fed's National Activity Index due at 8:30 a.m. EDT (1230 GMT).
* Halliburton Co shares rose 1.5 percent premarket after the world's No. 2 oilfield services provider reported a 20 percent increase in quarterly profit. The company also boosted share repurchases to $6 billion from $5 billion.
* EMC Corp jumped 4.7 percent premarket. Activist investor Elliott Management Corp acquired a $1 billion stake in the data storage equipment maker, and plans to push the company to spin off its VMware Inc unit, the Wall Street Journal reported. (Reporting by Rodrigo Campos; Editing by Jeffrey Benkoe)