Tens of thousands of people have gathered in South Sudan's capital for celebrations marking the new nation's independence.

South Sudan officially became the world's newest country at midnight local time Friday. Residents of the capital, Juba, celebrated with parties in the streets.

A huge crowd has now assembled at a stadium in Juba for the formal declaration of independence.

Scheduled speakers at the event include U.N. Secretary-General Ban Ki-moon and the president of northern Sudan, Omar al-Bashir. Mr. Bashir flew into Juba Saturday.

Southern Sudan voted overwhelmingly to split from the north in a January referendum. The vote stemmed from a 2005 peace deal that ended Sudan's two-decade civil war.

Already, South Sudan has been recognized by its northern neighbor. Sudan's minister for presidential affairs, Bakri Hassan Saleh, made the official announcement Friday on state television.

Saturday's ceremonies in Juba will include a proclamation of independence, the raising of the new South Sudanese flag, and the swearing-in of South Sudan's first president, Salva Kiir.

The celebration takes place at the John Garang Mausoleum — named after the leader of southern Sudanese forces during the long civil war. Garang died in a 2005 helicopter crash.

Saturday's festivities belie the challenges the new nation will soon face.

South Sudan is still trying to disentangle itself from the north, and the two sides have yet to resolve issues on borders and oil revenue. Sudan's army is currently fighting pro-southern Sudan elements in the northern-controlled state of Southern Kordofan.

On Friday, the U.N. Security Council approved a new peacekeeping force for South Sudan. The force will have up to 7,000 troops and 900 civilian police.