Brent and U.S. crude futures extended losses in a late-session drop on Monday, dragged down by a rapid selloff on Wall Street the first trading day after Standard & Poor's downgraded the United States.

In London, ICE Brent for September delivery traded as low as $103.30 a barrel, down more than $6 from Friday's settlement at $109.37.

On the New York Mercantile Exchange, crude for September delivery hit a session low of $81.07 a barrel, down $5.81.

(Reporting by Gene Ramos; Editing by Dale Hudson)