London Brent crude for August delivery was down 24 cents at $48.17 per barrel early on Monday, after settling down $2.50, or 4.9%, at $48.41 on Friday.

NYMEX crude for August delivery was down 26 cents at $47.38 per barrel, after closing down $2.47, or 4.9%, on Friday.

Oil prices were also under pressure as the British pound fell anew in early Asian trading on Monday, with investors still at a loss as to what happens next now that the country has voted to leave the EU.

Panama opened the long-delayed $5.4 billion expansion of its shipping canal amid cheering crowds on Sunday, despite looming economic uncertainty in the shipping industry and a heated battle over billions in cost overruns.

Hedge funds betting on summer gasoline demand raised their bullish bets on US crude futures last week, just before the market's crash on Friday on Britain's shock decision to leave the EU, trade data showed.

Russia and China sealed a raft of energy deals during President Vladimir Putin's visit to Beijing on Saturday, strengthening economic ties while pledging to preserve the strategic balance of power among nations.

Algeria's oil output will reach 69 million tonnes of oil equivalent in 2016, against 67 million tonnes last year, helped in part by increased production at existing fields, state energy company Sonatrach said on Sunday.