Saudi Arabia, the United Arab Emirates, Egypt and Bahrain closed transport links with top liquefied natural gas (LNG) and condensate shipper Qatar, accusing it of supporting extremism and undermining regional stability.
The news initially pushed Brent crude prices up as much as 1 percent as geopolitical fears rippled through the market. But Brent crude late reversed gains, trading down 50 cents, or 1 percent, at $49.45 a barrel by 2:34 p.m. EDT (1834 GMT).
U.S. West Texas Intermediate futures ended Monday's session at $47.40 a barrel, down 26 cents, or 0.6 percent. U.S. gasoline futures led the energy complex lower, falling about 2.4 percent to $1.5389 a gallon, on technical selling, brokers said.