June 30 (Bloomberg) -- Crude oil was little changed after rising to a record above $143 a barrel on concern Israel may attack Iran over its nuclear program and disrupt supply from OPEC's second-largest producer.

Pressure on Iran to end uranium enrichment and the falling value of the U.S. dollar may drive prices to $170 a barrel, OPEC President Chakib Khelil said June 28. Kuwait, the fourth-largest OPEC producer, is taking precautionary steps to export oil if Iran closes the Strait of Hormuz, Kuwait News Agency reported.

Concerns about Iran ``continue to persist and be in the air, which has helped prices,'' said John Kilduff, vice president of risk management at MF Global Ltd. in New York. ``More and more people are taking it seriously and giving it greater potential.'' Iran ``represents the mother of all supply disruption events.''

Crude oil for August delivery fell 21 cents to settle at $140 a barrel at 2:48 p.m. on the New York Mercantile Exchange after rising to a record $143.67. The price climbed 38 percent in the quarter, the biggest quarterly increase in nine years.

The U.S. won't allow Iran to shut the Strait of Hormuz, through which about 40 percent of Middle East oil is shipped, a spokesman for the Fifth Fleet said. ``They will not close it,'' Lieutenant Nate Christensen said in a telephone interview today from Bahrain, where the fleet is based. ``The Strait of Hormuz is vital international waters.''

Foreign ministers from the Group of Eight nations last week suggested more talks to coax Iran into opening its nuclear program to inspectors, after speculation the Islamic Republic faces an imminent Israeli strike.

Underlying Issues

``This is one of these issues where the more things change the more they stay the same,'' said Tim Evans, an energy analyst at Citigroup Global Markets Inc. in New York. ``Sometimes the market is more concerned about it than others, but nothing really has dramatically changed here in terms of the real underlying issues.''

Brent crude oil for August settlement fell 48 cents, or 0.3 percent, to $139.83 a barrel on London's ICE Futures Europe exchange, after reaching a record $143.91.

Goldman Sachs Group Inc., Wall Street's most profitable bank, said in a report that supply and demand, rather than speculators, are responsible for oil's rally. Goldman, which dominates the business of commodities trading along with Morgan Stanley, said revenue from commodities was higher in the second quarter than a year earlier.

`Excessive Speculation'

The U.S. House of Representatives last week approved a bill calling on the Commodity Futures Trading Commission to use its emergency powers to ``curb immediately the role of excessive speculation'' in any market it oversees where energy futures or swaps are traded.

The European Central Bank is expected to raise interest rates a quarter-percentage point to 4.25 percent, according to a survey of economists by Bloomberg News. The dollar has declined 7.3 percent this year against the euro, prompting some investors to buy commodities as a hedge against inflation.

Hedge fund managers and other large speculators almost doubled their bets on rising prices in the week ended June 24, according to U.S. Commodity Futures Trading commission data.

Net-long positions in New York oil contracts, the difference between contracts to buy and sell the commodity, rose to 24,217 contracts. Long positions climbed from a five-month low a week earlier while contracts to sell oil fell a second week to a two- month low.

To contact the reporter on this story: Robert Tuttle in New York at rtuttle@bloomberg.net

Last Updated: June 30, 2008 16:03 EDT