President Amadou Toumani Toure of Mali has formally resigned as part of a deal with coup leaders to end the crisis gripping the West African state.
International mediator Djibrill Bassole, Burkina Faso's foreign minister, confirmed a letter of resignation had been submitted.
The resignation paves the way for the coup leaders to step aside and the parliamentary speaker to take over.
Mali has been grappling with a separatist uprising in the north.
It intensified after the coup by army officers on 22 March.
Mr Bassole, who represents the West African regional bloc Ecowas, met Mr Toure in the Malian capital, Bamako.
"We have just received the formal letter of resignation from President Amadout Toumani Toure," he told reporters.
"We will now contact the competent authorities so that the vacancy of the presidency would be established and so that they take the appropriate measures."
Under the agreement, the Malian parliamentary speaker, Dioncounda Traore, will take over as interim president and govern with a transitional administration until elections are held.
Ecowas has lifted sanctions it imposed after the coup and an amnesty has been agreed for the coup leaders.
The coup, led by Capt Amadou Sanogo, took place amid concerns in the army that the government was not doing enough to supress the insurrection in the north.
Since the coup, key towns in northern Mali have fallen to Tuareg separatist rebels and their Islamist allies.
The Tuaregs have called for their newly-named territory of Azawad to be recognised as independent, although this notion has been dismissed by the international community.
There are two main groups behind the rebellion, namely the secular National Movement for the Liberation of Azawad (MNLA) and Ansar Dine, an Islamist group.
The latter has started to impose Sharia law in some towns.
The MNLA is made up partly of Tuaregs who had fought in Libya on the side of Col Muammar Gaddafi and returned to Mali after he was killed.
Human rights group Amnesty International has warned of a major humanitarian disaster in the wake of the rebellion.
Meanwhile, Ecowas is preparing a force of up to 3,000 soldiers which could be deployed to stop the rebel advance.
The Tuaregs, who inhabit the Sahara Desert in the north of Mali, as well as several neighbouring countries, have fought several rebellions over the years.
They complain they have been ignored by the authorities in Bamako.