The world has its newest nation – South Sudan, which celebrated its independence with ceremony in its capital, Juba, on Saturday.

A crowd of several hundred thousand roared when soldiers raised the new South Sudan flag and lowered the flag of the north.

Attendees also heard a formal declaration of independence and good wishes from a series of dignitaries, including the president of north Sudan, Omar al-Bashir.

The Republic of South Sudan became the world's newest country at midnight local time. Residents of Juba celebrated with parties in the streets.

The celebration continued with ceremonies at a Juba stadium named in memory of John Garang, who led southern forces during Sudan's long north-south civil war.

The last speaker, South Sudan President Salva Kiir, thanked countries and aid groups that helped feed and educate South Sudan's people during the conflict. He said South Sudanese must forgive but will never forget the suffering they endured.

In a call for peace, he said the members of his country's tribes must consider themselves South Sudanese first. He also announced an amnesty for militias that have fought the South Sudanese government in recent months.

Southern Sudan voted overwhelmingly to split from the north in a January referendum. The vote stemmed from the 2005 peace deal that ended the Sudanese 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. Egypt and the United States followed with recognition on Saturday.

The declaration of independence approved by South Sudan's parliament calls for a system of governance that upholds rule of law, justice, democracy, human rights and respect for diversity.

The head of the U.S. delegation, Ambassador Susan Rice, told the audience in Juba that South Sudan's future depends on strong government institutions that are free of corruption.

In the background of Saturday's festivities there are many challenges the new nation will face.

South Sudan has been wracked with deadly tribal and rebel violence, and has yet to resolve disputes with the north on borders and how to share oil revenue.

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.