Just two years after gaining independence in 2011, South Sudan descended into a devastating civil war that killed hundreds of thousands of people, forced millions from their homes and plunged parts of the country into famine.

On Saturday, the country's warring sides formed a transitional coalition government in what is seen as a significant step to create peace in a country ravaged by conflict.

More:

Here is a look at key events in South Sudan since independence.

2011: World's newest country

On July 9, 2011, South Sudan formally declares independence from Sudan following six years of autonomy and 20 years of war.

The proclamation of independence comes after a referendum that saw a nearly 99 percent vote in favour of secession.

Salva Kiir is sworn in as president, with Riek Machar as his deputy. The two men are rivals but also leaders in the Sudan People's Liberation Movement (SPLM) that led the push to secede from Sudan, which is now South Sudan's northern neighbour.

The new country takes over three-quarters of the oil reserves in Sudan which retains control of all pipeline and export facilities.

Other thorny issues are the tracing of their common border and the status of disputed regions such as Abyei.

2012: Oil clashes

The two countries clash for nearly two months starting March 2012 over rights to the oilfields around Heglig, a town just inside Sudan.

South Sudanese troops briefly occupy the area, which accounts for half of Sudan's crude oil production.

Arguments erupt over pipeline transit costs and Sudan confiscates millions of barrels of South Sudan crude.

South Sudan halts its production in January for more than a year accusing Khartoum of theft.

2013: Civil war

On July 23, 2013, Kiir fires Machar as well as all government ministers, their deputies and several police brigadiers.

On December 6, Machar accuses Kiir of "dictatorial" behaviour.

After a night of fighting in the capital, Juba, Kiir says on December 16 his forces had thwarted an attempted coup by Machar, who denies the claim.

Rival army units clash in Juba and the fighting spreads beyond the capital, fuelled by rivalries between Kiir's majority Dinka ethnic group and Machar's Nuer, the country's second-largest ethnic group.

The country descends into civil war marked by ethnic massacres, widespread rape, the recruitment of child soldiers and other atrocities.

2016: Machar back, briefly

Machar and Kiir sign a peace accord in August 2015 that provides for Machar's reappointment as vice president.

He returns to Juba and is sworn in on April 26, 2016.

But fighting between supporters of both leaders breaks out again in July. Machar goes into exile, accusing Kiir of trying to have him killed. He is replaced as vice president.

2018: Unity delays

On June 20, 2018, Kiir and Machar meet for the first time in two years.

On September 12, they sign a new peace agreement to end five years of war that killed more than 380,000 and forced roughly four million people from their homes.

It paves the way for a power-sharing government to be installed on May 12, with Machar again as the vice president.

Days before the deadline, they agree to a delay until November 12 because of outstanding differences.

On November 7, they extend the deadline by another 100 days.

Sticking points include the carving out of state boundaries, creation of a unified national army and protection for Machar.

2020: Coalition government

On February 22, Machar is finally sworn in as the first vice president after he and Kiir agree to move forward with a power-sharing government.

The two men have said outstanding issues will be negotiated under the new government.

Tens of thousands of rival forces still must be knitted together into a single army, a process that the United Nations and others have described as being behind schedule and poorly provisioned.

The current peace is extremely fragile, a UN report that was released on Thursday warned.

High-level corruption is rampant, militias are being armed and civilians deliberately starved, the Commission on Human Rights in South Sudan said in its report. More than half of the 12-million strong population face food shortages, it added.