Crude futures dropped to near a three-week low on Tuesday, as investors as closing monitoring Greek developments, after the country closed its banks amid its financial crisis.

Brent crude futures lost 3 cents to settle at $61.98 per barrel. It fell on Monday to $62.01 per barrel, its lowest level since June start.

U.S. crude closed down $1.30, or 2.2%, at $58.33 a barrel, its lowest settlement since June 8.