The first option would have a very mobile force of 6,000 UN troops backed by 20 helicopters and an observation aircraft.
The second option, which Ban favours, would deploy a more ground-based mission with about 10,900 soldiers, backed by 11 helicopters and two observation aircraft.
He also proposed that about 800 Chadian police be loaned to a UN peacekeeping operation, along with 260 international police.
Ban said that if the council decides to establish a peacekeeping mission, it should assist in protecting civilians who have fled their homes and in maintaining law and order in refugee camps. It should also deploy at key border locations to reduce tensions and prevent cross-border attacks.
In both options, the mission's military component would be based in Chad's capital, N'Djamena, with a liaison office in the Central African Republic's Bangui.
An operations headquarters would be located in Abeche in eastern Chad.
The force would be split into four sectors, including three in Chad and one in the Central African Republic.
Ban indicates in the report that he has taken steps for the deployment to the region of a mission to set the stage for the troop arrival.
Eastern Chad is facing "a multi-faceted security and humanitarian crisis" which includes ongoing clashes between government forces and Sudan-based Chadian fighters and cross-border attacks on civilians by Sudan-based militia, the report said.
The region also suffers ethnic violence, inter-communal tensions and banditry, which along with the other clashes have led to an increase in the number of internally displaced Chadians from an estimated 92,000 in December to approximately 120,000 by February 1, the report said.
In addition, Chad is hosting 232,000 refugees from Sudan, primarily from Darfur.
|A UN peacekeeping force would be based in|
Chad's capital but with operations in Abeche
Ban said the situation in the north-eastern Central African Republic was less acute following an agreement between the government and rebel groups to negotiate an end to their conflict.
The secretary-general said that "eastern Chad is not a conventional peacekeeping environment" because of unrest in the region, hostilities between the government and opposition groups, and the failure of efforts at political dialogue.
Ban said: "The open-ended deployment of a United Nations peacekeeping force into this challenging environment would therefore carry distinct and serious risks. Chief among these is the possibility that armed groups may view a United Nations force as interfering with their military agenda and decide to attack it."
A UN force could also find itself caught in cross-fire, he said.
To mitigate the risks, he recommended the larger 10,900-strong force as the best option.
Ban said it would be "imperative" for the UN to get assurances from Chadian armed groups "that they would recognise the impartial character of a United Nations presence".
The secretary-general stressed that the deployment of any UN force in eastern Chad would need full support from the government.
When Hedi Annabi, assistant secretary-general for peacekeeping, met Deby in eastern Chad on February 5, Ban said the president told him he had asked the council in November to deploy a "civilian force" to the camps - not a military one.
Ban said that a lasting solution in both countries depends foremost on their leaders.
Unlike his predecessor, Ban made no recommendation on whether the council should deploy a force.
In one of his final reports before stepping down as UN secretary-general on December 31, Kofi Annan recommended against deploying peacekeepers to the two countries until all parties agree to a ceasefire and start talks on a political solution. He cited the risk to troops from continuing hostilities and difficult logistics.
The Security Council rejected Annan's recommendation, and asked the UN team that had gone to Chad and the Central African to return to the region to make "updated and finalised recommendations on the size, structure and mandate of a UN multidimensional presence".