Oil has hovered near a three-year high above $US70 a barrel on signs that production cuts by OPEC and Russia are tightening supplies, although analysts warned of a "red flag" due to surging US production.

Oil has hovered near a three-year high above $US70 a barrel on signs that production cuts by OPEC and Russia are tightening supplies, although analysts warned of a "red flag" due to surging US production.