An ICC prosecutor has sought a warrant for Mr Bashir's arrest
Sudan's President Omar Hassan al-Bashir has announced an immediate ceasefire in the Darfur region of western Sudan.
He said his government would start disarming militias and restrict the use of weapons among armed groups.
Darfuri rebel groups did not take part in talks, and analysts have questioned the president's motivation.
Previous ceasefires have failed, while Mr Bashir has faced intense pressure after an international court prosecutor sought a warrant for his arrest.
The International Criminal Court prosecutor sought to indict him in July on charges of genocide, war crimes and crimes against humanity committed in Darfur.
The BBC's Amber Henshaw, in Khartoum, says the government hopes this plan will be enough to convince the international community to defer the case against Mr Bashir.
But similar declarations in the past have come and gone without making any difference on the ground in Darfur, she adds.
Up to 300,000 people have died and more than two million have fled their homes in Darfur since 2003.
Rebel groups began the conflict in 2003, but since then militia groups seen as having links to Mr Bashir's government have been held responsible for waves of violence against civilians.
Mr Bashir made the announcement after hearing the final recommendations of the Sudan People's Initiative (SPI), a government-backed plan to find peace for Darfur that did not involve any rebel groups.
The recommendations were expected to lay the foundation for a possible peace conference in Qatar.
ACCUSATIONS AGAINST BASHIR
Killing members of the Fur, Masalit and Zaghawa ethnic groups
Causing members of these groups serious bodily or mental harm
Inflicting conditions of life calculated to bring about these groups' physical destruction
Crimes against humanity:
Attacks on civilians in Darfur
Pillaging towns and villages
"I hereby announce our immediate unconditional ceasefire between the armed forces and the warring factions, provided that an effective monitoring mechanism is put into action and observed by all involved parties," Mr Bashir said.
The Justice and Equality Movement (JEM), a key rebel group, told the Reuters news agency on Wednesday that it could not agree to the ceasefire.
However, Sudanese Industry Minister Jalal al-Dugair, a spokesman for the SPI, told the BBC that the government would launch contacts with the rebel groups to promote the ceasefire.
Some diplomats believe the ceasefire announcement is a step in the right direction, our correspondent reports.
But the US charge d'affaires in Khartoum, Alberto Fernandez, told the BBC the challenge now would be to translate good ideas into a improvement on the ground for the people of Darfur.
"That was the challenge before the Sudan's People's Initiative, [and] it is still the challenge," he said.
Ali Hassan, the head of the Unamid peacekeeping force in southern Darfur, told the Associated Press the Sudanese government was to be praised for putting "something concrete on the table for discussion".
The proposal puts on the table "almost all the issues the rebels have demanded," Mr Hassan said, adding that the UN and Qatar would now work to bring the rebels into the ceasefire.
HAVE YOUR SAY
Although it seems unlikely - I really hope this lasts.
Dean, Birmingham, UK
One international observer told our correspondent that it was partly an attempt by the Sudanese government to put pressure on rebel groups to sign up to a 2006 peace agreement, which most rebels rejected.
There are also hopes that the announcement will put pressure on the international community to set up a monitoring force in Darfur, as no such force exists at the moment.
Interviewed by the BBC on Tuesday before Mr Bashir's announcement, Sudan's Foreign Minister Deng Alor said any ceasefire would not come as a direct response to the ICC, but might influence it.
"If we come up with the clear roadmap for Darfur, then I think we can have the moral authority to begin to ask... whether they could defer the decision by the ICC," he said.