JUBA: With his cowboy hat and thick charcoal beard, the leader of the world's newest nation, Salva Kiir, is a respected ex-rebel chief who shares the devout Christian faith of many of his South Sudanese people.

The towering 60-year-old president, who spent years as a guerrilla in the bush during the devastating 1983-2005 civil war between north and south, has repeatedly spoken out for peace during the sometimes deadly disputes that dogged the run-up to independence day for his fledgling nation on Saturday.

In sermons at the Roman Catholic cathedral in the still war-damaged capital Juba and in statements from his office, Kiir has repeatedly delivered a message of peace and reconciliation, and made war-time foe President Omar al-Bashir guest of honour at the independence celebrations.

“We will not go back to war, it will not happen,” Kiir insisted in May after northern troops marched into the disputed border district of Abyei which the southern leadership wants to make part of their new nation.

“We are committed to peace,” he said. “We fought enough. We made peace.”

Salva, as he is known in the south, never made any secret of his ambition to lead the vast, underdeveloped region of 8.5 million people to independence.

That is in contrast to his veteran predecessor John Garang, whose goal until not long before his death in 2005 was a united, federal and democratic Sudan.

Hailing from the Bahr al-Ghazal region, near Abyei, Kiir belongs to the Dinka tribe, south Sudan's largest ethnic group, and preaches at mass every Sunday in the Juba cathedral.

His people are traditionally cattle herders and he is rarely seen without his trademark Stetson. When senior US Senator John Kerry visited Juba for the January referendum in which southerners voted almost unanimously for independence, he brought a new hat as a present.

Kiir took over from the charismatic Garang, with whom he co-founded the rebel Sudan People's Liberation Movement in 1983, after the latter was killed in a helicopter crash in Uganda shortly after signing the 2005 peace agreement that ended the civil war.

Kiir at once became the group's political and military leader, president of the south and vice president of Sudan, which led to him working for six years alongside civil-war foe President Omar al-Bashir in a government of national unity.

A career military man who is more comfortable speaking in Juba Arabic dialect than in English, Kiir has failed to shake off the shadow of his predecessor, whose legacy is honoured by both southerners and northerners.

In the run-up to the January referendum, Kiir reconciled with most of the former rebels' domestic opponents.

But the world's newest head of state faces daunting challenges as leader of an ethnically divided nation which lacks even basic infrastructure and which has hundreds of thousands of returnees to reintegrate after the huge population movements triggered by the long years of civil war.