Mumbai, June 23 -- The Indian rupee plunged 23 paise to close at a five-month low of 86.78 (provisional) against the US dollar on Monday amid a strengthening dollar and volatile crude oil prices following the US strike on Iran's nuclear facilities. A sharp decline in the domestic equity markets further pressured the rupee. Indian shares fell on Monday, but ended off their day's lows as markets apparently took the U.S. strikes against nuclear targets in Iran in their stride and waited to see how Iran reacts and what happens to Tehran's nuclear program. The benchmark 30-share BSE Sensex hit an intraday low of 81,476.76 before closing down 511.38 points, or 0.62 percent, at 81,896.79. The broader NSE Nifty index ended down 140.50 points, or ...