NEW YORK -- Oil prices extended their declines Thursday, sliding below $100 a barrel at times as concerns about the economy and demand for oil grew and the dollar strengthened, according to the Associated Press.

Retail gas prices, meanwhile, fell further below their recent records, while diesel rose to a new record above $4 a gallon.

Light, sweet crude for May delivery dropped $1.76 to $100.78 a barrel on the New York Mercantile Exchange Thursday after sliding as low as $98.65 earlier. It was the first dip by a front-month oil contract under $100 since March 5.