NAIROBI, Kenya (CNN) -- The Kenyan government and its main opposition group have reached a four-point plan to end violence that has wracked the country for more than a month, former U.N. Secretary-General Kofi Annan announced at a news conference Friday.
His successor, Ban Ki-moon, who has also been involved in the mediation, said he was ""reasonably encouraged" by the political leaders' commitment to resolving the crisis. He said he told both Kenyan President Mwai Kibaki and Orange Democratic Movement leader Raila Odinga that the violence "has to stop."
The peace plan's first three items, to be completed within a 15-day period, are: stopping the violence and restoring fundamental rights; taking measures to address the humanitarian crisis; and promoting "reconciliation, healing and restoration," Annan said.
The fourth item, which could take up to a year, aims for a resolution to the political crisis, said Annan, who has overseen the recent mediation efforts.
The two sides also signed an 18-point plan to implement the promise to end the violence, Annan said. Watch Annan discuss what needs to be done »
The plan includes an agreement to disband illegal armed groups, to refrain from making "irresponsible and provocative" statements, and to hold joint meetings to promote peace and reconciliation. It also calls on police to end "brutality" and "excessive force."
"We expect to be able to conclude our work in a year," Annan said, adding that the negotiations' current pace could allow the sides to complete their work in a shorter time frame. "But the timetable is one year."
Meetings between the two sides will resume Monday and continue through the week, Annan said.
After Annan's announcement of the deal, Odinga urged his supporters to turn away from violence.
Odinga and President Mwai Kibaki have been feuding since the December 27 elections in which incumbent Kibaki kept his post. Odinga had blasted the results, saying the election was rigged, and he and his supporters declined to recognize the election as valid.
The post-election violence has carried ethnic overtones, as supporters of Kibaki, a member of the Kikuyu tribe, battle with followers of Odinga, from the Luo tribe.
At least 863 people have been killed and 261,000 driven from their homes since the turmoil began, according to the Kenyan Red Cross.
On Friday U.S. Secretary of State Condoleezza Rice reached out to Odinga by phone, urging him to work hard to follow through on implementing the political solution reached with Annan, State Department spokesman Sean McCormack said.
Rice also was expected to call Kibaki this weekend. Calls to both Odinga and Kibaki were encouraged by Annan, with whom Rice spoke by phone on Thursday, McCormack said.
Annan has also called for the "the protection and assistance and safe return of all internally displaced persons."
The World Health Organization on Friday issued a statement saying many internally displaced Kenyans were living in crowded makeshift camps with "poor shelter, water supply, sanitation ... food shortages, no cooking fuel, precarious access to health care and shortages of antibiotics."
Representatives of both sides flanked Annan and echoed his calls to end the violence.
"We also expect the public to be a responsible public," said Musalia Mudavadi, an ODM member. "We are calling on the Kenyan people to uphold the rule of law, to make sure that incidents of violence -- revenge, retaliation -- are dealt with. "
The two sides have made substantial progress on the first agenda item of curbing violence, he said.
"We expect everybody from public to police to other law enforcement agencies ... to be guided by rule of law," said Martha Karua, Kenya's minister of justice and constitutional affairs. "We can only enjoy our fundamental freedoms by respecting each others' rights." E-mail to a friend
CNN's Zain Verjee and Elise Labott contributed to this report.
Copyright 2008 CNN. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed. Associated Press contributed to this report.