U.S. oil fell for a second day on Tuesday, amid little sign of progress on U.S.-China trade talks, while Saudi Arabian crude output rose, reinforcing concerns about a glut.
U.S. West Texas Intermediate (WTI) crude was down 20 cents, or 0.4%, at $56.66 a barrel by 0039 GMT. The contract dropped 0.7% in the previous session.
Brent crude futures were yet to trade after falling 0.5% on Monday.
Worries about the impact on oil demand from the fallout of the 16-month U.S.-China trade war, which has weighed on global economic growth, have returned after doubts were cast on the chances of a so-called phase one agreement.