NEW YORK - Oil prices made their biggest single-day leap ever yesterday - clearing $139, dragging the Dow Jones industrials down nearly 400 points and raising the once-unthinkable prospect of $150 oil and even higher gas prices by the Fourth of July.

The meteoric rise of nearly $11 for the day piled atop an increase of almost $5.50 the day before, taking oil futures more than 13 percent higher in just two days, easily a record on the New York Mercantile Exchange.

And those weren't the only stunning numbers of the day: The government also reported the nation's unemployment rate zoomed to 5.5 percent in May, a monthly rise of half a percentage point, the biggest in 22 years.

Oil surged higher after Morgan Stanley analyst Ole Slorer predicted strong demand in Asia and tight supplies in the Western Hemisphere could drive prices to $150 by Independence Day, when millions of Americans take to the roads. That means no end in sight for spiraling gas prices, already above $4 per gallon in much of the country.

Even longtime market observers were shocked by the magnitude and speed of oil's rally.

"We're into unchartered territory, and somewhat off the map as far as historical precedents are concerned," said Jim Ritterbusch, president of energy consultancy Ritterbusch and Associates in Galena, Ill.

Besides the jump in the unemployment rate, the Labor Department said employers had cut 49,000 jobs in May, the fifth straight month of nationwide losses. Job losses for the year reached 324,000.

The White House said President Bush was considering further plans to help energize the economy, already teetering on the edge of recession and crippled by a tumbling housing market and other factors.

On Wall Street, the Dow plunged 394.64 points, more than 3 percent, to close at 12,209.81, the biggest drop in more than 15 months in both percentage and points terms.

Oil traders also zeroed in on remarks by an Israeli Cabinet minister who was quoted as saying his country will attack Iran if it doesn't abandon its nuclear program. Transportation Minister Shaul Mofaz added that Iranian President Mahmoud Ahmadinejad "will disappear before Israel does," the Yediot Ahronot daily reported.

Iran is the second-biggest oil producer in the Organization of Petroleum Exporting Countries, and traders worry that any conflict with Israel could disrupt global supplies. *