Asia witnessed a fall in oil prices below $66 a barrel on Monday, as regional stock markets plunged and investors predicted a slide of economic data this week, which will help shed light on the health of the U. S. economy.

In electronic trading on the New York Mercantile Exchange, benchmark crude for November delivery was down 40 cents at $65.62 a barrel by midday Singapore time. The contract added 13 cents to settle at $66.02 on Friday.

Since Japan's market was hit by the yen reaching a nine-month high against the dollar, Asian stocks were weaker. Concerns over recovery prospects in the world's largest economy were ignited by reports on manufacturing and home sales.

"Crude is flirting with the bottom of a $65 to $75 trading range that has held for months as traders weigh signs of an improving global economy against evidence that consumer demand remains weak," said a source.

The Labor Department's monthly jobs report on Friday will be the most closely watched economic indicator. Apart from this, reports on home prices, manufacturing, consumer confidence, construction spending and factory orders would also be acquired by investors.

A fall in gasoline for October delivery was evident in other Nymex trading by 0.55 cent to $1.62 a gallon. While natural gas climbed 1.0 cent to $4.00 per 1,000 cubic feet, heating oil was steady at $1.68 a gallon.

Brent crude plunged 41 cents to $64.70 on the ICE Futures exchange in London.