A three-and-a-half-year-old conflict in Sudan's western Darfur region has spilled over the border into eastern Chad and the northern CAR, prompting angry tirades from both governments against al-Bashir's government.
Khartoum in turn has accused N'Djamena of backing the fighters in Darfur.
Ali al-Triki, the Libyan foreign minister, said the meeting in Tripoli would focus on how to "improve the performance of African (Union) forces in Darfur and to increase their number to 17,000 men" from the current figure of some 7,000.
Another Libyan official, who spoke on condition of anonymity, said Tripoli was keen to find a "radical solution to the Darfur crisis to avoid the deployment (there) of international forces."
The aim was also to persuade the more inflexible anti-government groups in Sudan to sign up to a peace accord, he said, stressing that "a deployment of international forces in the thick of conflict" would not achieve results.
The latest initiative follows a visit to Tripoli by Deby earlier this month.
In Geneva on Tuesday, UN chief Kofi Annan said he expected a response from the Sudanese government by Wednesday at the latest on outstanding issues regarding last week's deal for a hybrid UN-AU force for Darfur.
Khartoum had wanted to consult on the size of the force, which the UN foresees at 17,000 troops and 3,000 police; the way the force commander should be appointed and the role of the special representative who would report to both the UN and the AU, Annan said.
|Kofi Annan's term as secretary-general of|
the UN ends on December 31
Earlier on Tuesday, a US envoy pressed Sudan to allow UN peacekeepers into the Darfur region by the end of the year to help end nearly four years of fighting that has claimed more than 300,000 lives.
Andrew Natsios, George W Bush's envoy to Sudan, said he was encouraged after Khartoum last week agreed in principle to a UN force.
Natsios said in Washington: "I really think that if we want to get this resolved, January 1 needs to be the deadline."
However, comments from the Sudanese government suggest Khartoum is already wavering about whether it stands by the accord reached in Addis Ababa, Ethiopia last week.
In August the UN Security Council cleared the way for sending up
to 20,000 UN peacekeepers to Darfur, but Sudan's government, whose
approval is required, has resisted a deployment.
In talks in Addis Ababa on Thursday, a "hybrid" force that would include both African and UN elements was discussed.
In a joint statement, Sudanese envoys agreed in principle to a UN force in place of the current 7,000 AU troops.
Since then, some Sudanese officials have expressed support for UN troops on the ground, but others said Sudan will only accept financial and logistical aid from the UN.
In a separate development a group of former rebels in Darfur have accused the government of violating a ceasefire by launching joint attacks with Janjawid militia that killed up to 80 civilians in South Darfur.
A Sudanese army spokesman said he had no information of any attack in the area of Um Beyy in the eastern region of South Darfur and denied any arming or support of militias.
"We have decided not to renew the technical agreement with NRC in South Darfur state..."
Mohamed Salih, head of international relations department for South Darfur
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A spokesman for the Sudan Liberation Movement (SLM), the only one of three rebel factions to sign a May peace accord with the government, warned Khartoum that if the attacks continued, their relations would return to "square one".
Al-Tayyib Khamis, a SLM spokesman said the Janjawid were using vehicles and arms given to them by the government.
An army spokesman said: "We don't even have any information that there was an attack so of course we were not involved."
The AU could not immediately give any information on the incident.
In another development, Sudan has ordered the Norwegian Refugee Council (NRC) to leave South Darfur state, accusing the aid agency of espionage and publishing false information.
Mohamed Salih, the head of the international relations department for South Darfur, said: "We have decided not to renew the technical agreement with NRC in South Darfur state.
"They have made reports on military movements of armed forces ... which is in the domain of espionage."
Earlier this month NRC said as a result of "frequent disruption" of its work it was closing down many of its operations in Darfur.
The organisation said it had been suspended five times for a total of 210 days since it started its aid effort in the middle of 2004.
Tomas C Archer, NRC's secretary-general, said at the time: "We cannot work when the authorities suspend us continuously and do not respond to our repeated requests for dialogue aimed at addressing and resolving underlying reasons for this action."