Silver and gold prices are climbing as developing crises from Portugal's financial problems to uprisings in the Middle East are prompting investors to buy more stable assets.
Silver for May delivery rose 92.9 cents, or 2.6 percent, to settle at $37.198 an ounce. Gold for May delivery gained $10.40 to settle at $1,438 an ounce.
Portugal's minority government neared collapse as lawmakers were poised to vote against its proposal for more austerity measures designed to avoid a bailout. The political upheaval could lead to more turbulence for the 17 nations that use the euro.
Meanwhile, speculation lingered about supply disruptions in the oil-rich region of the Middle East and North Africa as uprisings continued in a number of countries, including Libya.
Investors are nervous as they wonder how those events will play out. That has supported precious metals, which have the reputation of being safer assets to hold during uncertain economic times.
"There has been a large demand for safe-haven commodities of late," said Dave Meger, vice president of metals trading at Vision Financial Markets.
In other trading, metals used in manufacturing rose on expectations of continued robust demand from emerging markets, particularly China and the rebuilding of Japan after the devastating March 11 earthquake and tsunami.
"There's just a voracious appetite for base metals at this point in time and copper really is the lead of those," Meger said.
May copper added 11.55 cents to settle at $4.4285 a pound, April platinum rose $20.60 to settle at $1,760 an ounce and June palladium gained $11.45 to settle at $749.30 an ounce.
Oil prices rose after the government said gasoline demand continued to grow stronger despite a sharp increase in prices at the pump.
Benchmark crude for May delivery added 78 cents to settle at $105.75 a barrel on the New York Mercantile Exchange.
In Nymex trading for April contracts, heating oil fell 2.12 cents to settle at $3.055 per gallon, gasoline added 1.68 cents to $3.0213 per gallon and natural gas gained 8.1 cents to $4.335 per 1,000 cubic feet.
Grains and beans lost ground. In May contracts, wheat fell 8 cents to settle at $7.1425 a bushel, corn lost 5.75 cents to $6.81 a bushel and soybeans gave up 14.25 cents to $13.5125 a bushel.
Associated Press writer Barry Hatton in Lisbon contributed to this report.