"By any measure, Muammar Gaddafi's government has violated international norms and common decency and must be held accountable," Obama said in a statement after he issued an executive order in this regard late last night.
"These sanctions therefore target the Gaddafi government, while protecting the assets that belong to the people of Libya," he said.
The executive order issued by him blocks the property and interests in property of a number of individuals including the family members of the 68-year-old Libyan leader, officials of the Libyan Government and those responsible for human rights violations in that country.
The Libyan government's continued violation of human rights, brutalisation of its people and outrageous threats have rightly drawn the strong and broad condemnation of the international community, he said.
The US has been asking international community to act selectively against Gadaffi regime for its brutalities against anti-regime protestors.
Obama said, the US will continue to closely coordinate its actions with the international community, including its friends and allies and the United Nations.
"We will stand steadfastly with the Libyan people in their demand for universal rights, and a government that is responsive to their aspirations. Their human dignity cannot be denied," Obama said.
In a letter to the Speaker of the US House of Representative and Senate President, Obama said that the actions of Gaddafi, his government, and close associates constitute an "unusual and extraordinary threat" to the national security and foreign policy of the United States.
"The order declares a national emergency to deal with this threat," Obama said.
Obama''s Executive Order blocks the property and interests in property of the Government of Libya.
"I further find that there is a serious risk that Libyan state assets will be misappropriated by Gaddafi, members of his government, members of his family, or his close associates if those assets are not protected," the executive order said.
The order said, "The foregoing circumstances, the prolonged attacks, and the increased numbers of Libyans seeking refuge in other countries. The attacks have caused a deterioration in the security of Libya and pose a serious risk to its stability. Also, constituted an unusual and extraordinary threat to the national security and foreign policy of the United States, and I hereby declare a national emergency to deal with that threat."