The US government Thursday gave BP 24 hours to outline its next steps to contain the Gulf of Mexico oil spill, saying efforts to cap a fractured well were entering a "critical stage."The US pointman in the crisis, Thad Allen, wrote to BP managing director Bob Dudley saying that after talks planned for Friday the British energy giant must hand over "detailed plans and timelines. "BP is preparing to replace the containment cap on the ruptured wellhead with a more secure seal and hook up a third containment ship to the system to capture more of the oil leaking into the Gulf since April. "To approve these potential actions, I must have knowledge of the steps and decision points involved," Allen wrote, highlighting that while the measures were being carried out the amount of oil pouring into the Gulf could increase. Allen said he wanted to know the "mitigation efforts to be implemented and contingency plans if these efforts are not successful. "He said there are five key points that BP must provide: -- an updated timeline to hook up the Helix Producer containment ship to the system to start collecting oil -- a contingency plan if BP's move to fit a new containment cap fails -- a plan for pressure-testing the ruptured well and moving towards shutting it down completely -- a detailed timeline for completing two relief wells aimed at capping the leak permanently -- a plan on how to manage any oil reaching the surface, including the use of dispersants, skimming and burning operations.