Yemenis concluded a national dialogue Saturday aimed at drafting a new constitution and establishing a federal state in an impoverished country gripped by unrest, where southerners are clamouring for independence.
Secessionists boycotted the talks launched in March 2013 as part of a UN-backed transition that saw president Ali Abdullah Saleh step down after 33 years in power following massive Arab Spring-inspired protests in the region's poorest country.
Saleh's successor, President Abdrabuh Mansur Hadi, pledged at a ceremony on Saturday to form commissions to draft the new constitution and thrash out the details of the promised new federation.
"All (sides) have made painful concessions," Hadi said of the dialogue, which had been due to last six months but was extended for another four in the face of bitter disagreements over key issues.
"This is a historic day," said UN Secretary General Ban Ki-moon in a recorded video message played during the ceremony.
His envoy to Yemen, Jamal Benomar, who has been overseeing the implementation of the peace deal, hailed the outcome of the dialogue as a "clear roadmap".
"The dialogue was not a picnic, and faced tough challenges," said Benomar, adding that the Yemeni people "should be proud of this achievement".
EU foreign policy chief Catherine Ashton in a statement called the process "a unique and historic achievement", saying it had brought Yemen "closer to democracy and to the aspirations of its people for a more secure and prosperous future".
The United States also welcomed the conclusion of the dialogue, but State Department deputy spokeswoman Marie Harf said that "despite significant progress" Yemen's "democratic transition is not complete".
Southerners have strongly opposed proposals for a federation of six units -- four in the north and two in the south -- instead of one each for the formerly independent north and south, fearing that their influence would be diluted.
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"We will work as soon as possible to form a regions committee and another to draft a constitution," Hadi said at the ceremony attended by representatives of the United Nations, Arab League and Gulf states.
"We still have a long way to go to implement the document," said the president, who is himself originally from the south.
Benomar urged southerners to "react positively" to the outcome of the dialogue, taking into consideration the proposed "solutions to the south issue that all have signed".
Participants in the national dialogue agreed that Hadi should continue in office until a new president is elected, a process that could take years as the new constitution and electoral law are thrashed out.
Southern parts of Yemen formed an independent state from the end of British colonial rule in 1967 until union with the north in 1990.
A secession attempt four years later sparked a brief but bloody civil war that ended with northern forces taking over the south.
Southern separatists boycotted the dialogue, amid frequent clashes with security forces.
Zaidi Shiite rebels in the far north have meanwhile fought an on and off war with both the central government and hardline Sunni Islamists since 2004.
Al-Qaeda militants also continue to pose a major threat to Yemen's security despite repeated government campaigns against jihadists.
Al-Qaeda in the Arabian Peninsula, formed in Yemen in 2009 through a merger between the group's Saudi and Yemeni branches, has been linked to a number of failed attacks on the United States, which views it as the world's most dangerous Al-Qaeda affiliate.