Middle East crude benchmarks Oman and Dubai jumped to their highest since November on Tuesday as robust refining margins spurred demand in Asia. Complex refining margins in Asia are at their highest in more than three months, boosted by strong profits for gasoline, middle distillates and low-sulphur fuel oil. Brent's premium to Dubai crude is also at its widest since November, making Atlantic Basin grades more expensive for Asian refiners. Iran said on Monday that Washington had to make a "political decision" regarding lifting sanctions on the Islamic Republic as Tehran's demand for their full removal to revive a 2015 nuclear deal with world powers was non-negotiable.