Iran appointed oil ministry official Ali-Mohammad Mousavi as its new representative to the Organization of the Petroleum Exporting Countries known as OPEC.
Mousavi will replace Afshin Javan, the Oil Ministry's SHANA news agency reported on Tuesday.
Oil prices rose on Tuesday after data showed China's manufacturing activity expanded in December, but they are on track to end lower for a second consecutive year due to demand concerns in top consuming countries.
Brent crude futures rose 57 cents, or 0.8%, to $74.56 a barrel as of 0730 GMT. US West Texas Intermediate crude gained 58 cents, or 0.8%, to $71.57 a barrel. For the year, Brent declined 3.2%, while WTI was down 0.1%.