US STOCKS-Wall St tumbles as investors flee equities on Greek debt crisis
* Greece will not pay IMF on Tuesday: Govt official
* All 10 S&P sectors in the red; deepen losses in afternoon
* CBOE Volatility index spikes
* Quarter end, upcoming jobs report, Puerto Rico affect investors
* Euro STOXX 50 index - biggest one-day fall since 2011
* Indexes down: Dow 1.95 pct, S&P 2.09 pct, Nasdaq 2.4 pct (Updates with close, adds market commentary,)
By Sinead Carew
June 29 (Reuters) - U.S. stocks fell sharply in heavy trading on Monday and the S&P 500 and the Dow had their worst day since October after a collapse in Greek bailout talks intensified fears that the country could be the first to exit the euro zone.
The European Central Bank froze funding to Greek banks, forcing Athens to shut banks for a week to keep them from collapsing. Continuación...