World Bulletin / News Desk
The Dow fell 51 points to begin the day at 21,132 while the S&P 500 lost 6 points to 2,429.
The Nasdaq slipped 14 points to start trading at 6,280.
At the first bell, American benchmark West Texas Intermediate was trading at $47.13 a barrel with a 0.4 percent decline, while international benchmark Brent crude was trading at $49.15 per barrel -- a 0.5 percent loss.
Oil prices continued to remain under pressure after several Gulf states, including Saudi Arabia, cut diplomatic ties with Qatar on Monday, citing national security concerns.
The deteriorating relations risk the successful implementation of the OPEC deal which was extended last month to limit member countries' oil production levels through next March, according to experts.