WASHINGTON - Wary that Libya's crisis could devolve into humanitarian chaos, US President Barack Obama insisted he is considering every intervention option, including military might, along with America's allies. To Muammar Gadhafi, he declared: "Step down from power and leave."

Obama made clear on Thursday that he has not ruled out establishing a no-fly zone over Libya to prevent Gadhafi's air forces from bombing rebels. His broad assurance came one day after his defense chief, Robert Gates, said bluntly that a no-fly zone would amount to an act of war.

"I don't want us hamstrung," Obama said. Still, the president made clear he does not intend to act without the consent of international peers, and that the emphasis of the United States is on helping refugees, heading off a humanitarian crisis and hastening the end of Gadhafi's reign.

"There is a danger of a stalemate that, over time, could be bloody," Obama said in an appearance with visiting Mexican President Felipe Calderon. "And that is something that we're obviously considering. So what I want to make sure of is that the United States has full capacity to act, potentially rapidly, if the situation deteriorated in such a way that you had a humanitarian crisis on our hands."

Associated Press