NEW YORK, Dec. 27 (Xinhua) -- Oil futures rose Thursday for a fourth day to close near 97 dollars a barrel after government reports showed U.S. crude inventories fell for a sixth week and as geopolitical tensions escalated after former Pakistani Prime Minister Benazir Bhutto was assassinated. Crude for February delivery ended the session up 65 cents to 96.62 dollars a barrel on the New York Mercantile Exchange. Earlier it rose to an intraday high of 97.79 dollars in electronic trading. In its weekly inventory report, the Energy Department's Energy Information Administration said oil inventories fell by 3.3 million barrels in the week ending Dec. 21, more than double the 1.3 million barrel decline analysts expected. Pakistani opposition leader Benazir Bhutto died after a suicide bombing that also killed at least 20 others after a political rally in Rawalpindi, Pakistan. Pakistan, while not a major oil producer, holds nuclear weapons, and the death of Bhutto could increase tensions in the region.