PHILADELPHIA INQUIRER AND ASSOCIATED PRESS

Gas prices went up overnight again in Philadelphia: Following a 4-cent increase over the weekend, the average in the city and its four surrounding counties went up by 1 cent, to $3.10, according to AAA Mid-Atlantic.

South Jersey's average remains as $2.91.

The national average rose by 1 cent overnight, to $2.96.

Diesel prices rose overnight by 1 cent, the auto club said: to $3.45 in Philadelphia; to $3.11 in South Jersey; and to $3.22 in the nation overall.

Meanwhile, oil prices rose to a two-year high above $90 a barrel due to the effects of a weaker dollar and as icy weather in Europe and the United States increased demand for fuel.

At the early-afternoon mark in Europe, benchmark oil for January delivery was up $1 to $90.38 a barrel in electronic trading on the New York Mercantile Exchange. The contract hit $89.76 on Monday before pulling back to settle at $89.38, up 19 cents.

Oil prices have climbed more than $10 in the last two weeks, partly due to worries that the debt crisis affecting some countries using the euro could spread.

This "shows that there is a strong upside momentum in the oil market," supporting OPEC officials' views that crude oil prices might reach the $100-per-barrel area in 2011, said analysts at Sucden Financial in London.

If oil prices remain above $90 - the top of the range considered "comfortable" by the world's main oil exporters - it could hold back higher demand and stifle economic growth.

"In other Nymex trading in January contracts, heating oil rose 2.66 cents to $2.5023 a gallon, gasoline added 1.45 cents to $2.3562 a gallon and natural gas gained 5.6 cents to $4.545 per 1,000 cubic feet.

In London, Brent crude advanced $1.04 to $92.49 a barrel on the ICE Futures exchange.