UN Secretary-General Ban Ki-moon and Arab League chief Nabil Elaraby on Thursday appointed Ban's predecessor Kofi Annan as joint special envoy on the Syrian crisis, the United Nations announced.

Annan "will provide good offices aimed at bringing an end to all violence and human rights violations, and promoting a peaceful solution to the Syrian crisis," a UN statement said.

It said that Annan will be guided by last week's resolution of the UN General Assembly, which endorsed an Arab League plan for Syrian President Bashar al-Assad to step aside, and other Arab League decisions on Syria.

"He will consult broadly and engage with all relevant interlocutors within and outside Syria in order to end the violence and the humanitarian crisis," the statement said.

Annan will also "facilitate a peaceful Syrian-led and inclusive political solution that meets the democratic aspirations of the Syrian people through a comprehensive political dialogue between the Syrian government and the whole spectrum of the Syrian opposition."

The United Nations says that over 5,400 civilians have been killed in Syria's 11-month crackdown on anti-Assad demonstrators inspired by other Arab Spring uprisings across the Middle East and North Africa.

Annan was UN secretary-general from 1997 through 2006. After leaving the world body he helped negotiate an end to violence in Kenya that killed 1,220 people after the African nation's December 2007 election.

While at the helm of the United Nations, Annan angered Washington and London when he declared that their 2003 invasion of Iraq was "illegal."

In 2006, Annan said that he feared he would end up being remembered only for the oil-for-food program for Iraq, saying blame for that financial scandal was misdirected.

One of his top regrets as secretary-general, he added, was that the allegations of UN mismanagement of the $64 billion Iraqi humanitarian program had been "exploited to undermine the organization (the UN)."