"It is US policy that Gaddafi needs to go. We have got a wide range of tools in addition to our military efforts to support that policy.
We were very rapid in initiating unilateral sanctions and then helping to mobilize international sanctions against the Gadhafi regime," the US President said during a joint news conference with his Chilean counterpart Sebastian Pinera in Santiago, Chile.
Obama said the US military action is in support of an international mandate from the Security Council that specifically focuses on the humanitarian threat posed by Colonel Gaddafi to his people.
"Not only was he carrying out murders of civilians, but he threatened more; he said very specifically: We will show no mercy to people who live in Benghazi," he said.
"In the face of that, the international community rallied and said, we have to stop any potential atrocities inside of Libya, and provided a broad mandate to accomplish that specific task.
As part of that international coalition, I authorized the US military to work with our international partners to fulfill that mandate," Obama said.
The US froze assets that Gaddafi might have used to further empower himself and purchase weapons or hire mercenaries that might be directed against the Libyan people, he said.
"So there are a whole range of policies that we are putting in place that has created one of the most powerful international consensuses around the isolation of Mr.
Gaddafi, and we will continue to pursue those," he added.
However, America's military action is in support of the UN Security Resolution 1973.
That specifically talks about humanitarian efforts.
"We are going to make sure that we stick to that mandate," he said.
"With respect to initiating this action while I was abroad, keep in mind that we were working on very short time frames. We had done all the work, and it was just a matter of seeing how Gaddafi would react to the warning that I issued on Friday", the US President Obama said.
"After consultation with our allies, we decided to move forward. And it was a matter of me directing Secretary of Defense (Robert) Gates and Admiral (Mike) Mullen that the plan that had been developed in great detail extensively prior to my departure was put into place," he added.