President Obama on Saturday morning announced that the U.S. has formally recognized the world's newest country, South Sudan. He also warned mostly Arab Sudan to fully implement its peace agreement with South Sudan.

South Sudan came into existence Saturday after decades of civil turmoil within Sudan. Tensions remain over establishing the border and access to oil fields in the south. 

“I am proud to declare that the United States formally recognizes the Republic of South Sudan as a sovereign and independent state upon this day, July 9, 2011.  After so much struggle by the people of South Sudan, the United States of America welcomes the birth of a new nation,” Obama declard.

“A proud flag flies over Juba and the map of the world has been redrawn. These symbols speak to the blood that has been spilled, the tears that have been shed, the ballots that have been cast, and the hopes that have been realized by so many millions of people,” he wrote.

“Lasting peace will only be realized if all sides fulfill their responsibilities,” Obama warned. “The Comprehensive Peace Agreement must be fully implemented, the status of Abyei must be resolved through negotiations, and violence and intimidation in Southern Kordofan, especially by the Government of Sudan, must end.”

Residents of southern Sudan voted in January to secede and for a new nation. Residents of the border region of Abyei have yet to decide in which country they will reside due to a postponed vote. U.S. officials fear that border tensions could spark a war between South Sudan and Sudan.

Secretary of State Hillary ClintonHillary Diane Rodham ClintonGeorge HW Bush wears 'book socks' to Barbara Bush's funeral to honor her passion for literacy Obamas, Clintons to attend funeral of Barbara Bush Hillary Clinton to fundraise in DC for public charter high school MORE joined Obama in congratulating South Sudan.

"The realization of this historic day is a testament to the tireless efforts of the people of South Sudan in their search for peace. We commend South Sudan’s current leaders, including President Salva Kiir Mayardit, for helping guide Southern Sudan to this moment," she said. Her statement made no mention of Sudanese President Omar al-Bashir, who has been indicted for war crimes and for genocide in the Darfur region by the International Criminal Court in The Hague.