BP’s top executive acknowledged Thursday the global oil giant was unprepared to fight a catastrophic deepwater oil spill as engineers were forced yet again to reconfigure plans for executing their latest gambit to control the Gulf of Mexico gusher.

BP PLC planned to use giant shears to cut a pipe a mile below the sea after a diamond-tipped saw became stuck halfway through the job, another frustrating delay in six weeks of failed efforts to stop or at least curtail the worst oil spill in U.S. history. The government’s point man for the disaster, Coast Guard Adm. Thad Allen, said on the NBC “Today” show the cut would be made later Thursday.