WASHINGTON: US President Barack Obama said he wanted to know "whose ass to kick" over the Gulfof Mexico oil spill, adding to the pressure on energy giant BP Plc as it sought to capture more of the leak from its gushing well. "I don't sit around just talking to experts because this isa college seminar. We talk to these folks because they potentially have the best answer so I know whose ass to kick," Obama said in an interview. They were the angriest words yet about the catastrophe from Obama, who has been criticized for his response to the worst oil spill in U.S. history. Obama reiterated that all those affected should be adequately compensated. The stakes remain high for all involved from Gulf Coast communities devastated by the disaster to Obama and his domestic standing to BP and its battered reputation with the public and investors.