The unemployment rate increased to 5.5 percent in May from 5 percent in April, marking the biggest increase since February 1986, the U.S. Labor Department said today. The dollar dropped as much as 1 percent against the euro. Gold has gained 33 percent in the past 12 months as a slump by the dollar boosted demand for the metal as an inflation hedge.

``The dollar is much weaker, and that's what is creating the bounce in the market,'' said Leonard Kaplan, the president of Prospector Asset Management in Evanston, Illinois.

Gold futures for August delivery rose $23.50, or 2.7 percent, to $899 an ounce on the Comex division of the New York Mercantile Exchange. That marks the biggest gain for a most- active contract since Nov. 23.

The jump in the jobless rate was higher than every forecast in a Bloomberg survey of 79 economists, who had estimated a median gain to 5.1 percent. U.S. payrolls dropped by 49,000 last month after a 28,000 drop in April.

``The dollar took a nose dive as soon as this jobs data came out, and that's a big reason we've seen gold move up,'' said Matthew Zeman, a trader at LaSalle Futures Group in Chicago.

The euro reached $1.5751 today. It climbed to a record $1.6019 on April 22.

Energy Costs Jump

Gold also gained as a surge in energy costs added to speculation inflation will accelerate, Kaplan of Prospector Asset Management said.

Crude-oil futures for July delivery jumped as much as $11.22 to a record $139.01 a barrel today. The price was at $138.52 as of 2:31 p.m. in New York. Most-active futures have more than doubled in the past year.

Crude oil's rise ``was the prime catalyst, aside from the jobs data'' for gold's rally, Jon Nadler, an analyst at Kitco Minerals & Metals Inc., said in an e-mail.

Silver futures for July delivery advanced 26 cents, or 1.5 percent, to $17.43 an ounce. The metal is up 27 percent in the past year.

Gold may climb to $930 and silver will rise above $18 by mid-July, Sandeep Rungta, a metals strategist at Proficient Commodities in Kolkata, India, said in a report.

``Today's unemployment number was a big blow for the dollar, and we see the euro making fresh highs,'' Rungta said.