* Libya fears Mali Islamists will flow into neighbours
* Says its own internal security at stake
* Algeria gas attack re-energised jihadi militants (Adds details)
By Richard Lough
ADDIS ABABA, Jan 24 (Reuters) - United Nations peacekeepers should be deployed in Mali once a French-led offensive against al-Qaeda backed militants is over to prevent uprooted Islamist fighters destabilising neighbouring countries, a Libyan minister said on Thursday.
Foreign Minister Mohammed Abdulaziz said Libya's internal security was at stake, warning of the dangers of a spillover of Mali's crisis.
"Our vision is that when the operation ends, the Security Council should consider deploying a limited peacekeeping force in the area," Abdulaziz told reporters on the sidelines of an African Union summit in Ethiopia.
The peacekeepers should be part of a broader military exit strategy - what the minister called preventative diplomacy - that regional powers and Western governments needed to start thinking about now.
"If there is no preventive diplomacy... it will be very difficult to sustain security in the area," Abdulaziz said.
Warplanes from France, the former colonial power, have been attacking Islamist rebels in Mali for two weeks as African troops assemble to launch a U.N.-backed military intervention to oust insurgents who seized control of northern Mali in April.
One of the triggers for the Mali crisis was the return from Libya of heavily armed fighters once in the pay of deposed Libyan leader Muammar Gaddafi, say regional security experts. These gunmen and the wide availability of arms during the Libyan conflict inflated the ranks of separatist and Islamist groups who launched attacks on Mali's army in early 2012.
Libya is now worried about an exodus of Malian and foreign Islamist fighters as a result of the Mali crisis, and the smuggling of weapons if the vast country's desert borders cannot be secured.
The Tripoli government has been beset by internal rifts and security remains a major concern more than a year after Gaddafi's ouster.
"We know that if the situation in Mali deteriorates, it will have serious consequences in Libya," the minister said.
Last week's attack on a gas plant in Algeria - launched by Islamists opposed to a French-led military drive against al Qaeda-linked militants in Mali - have heightened fears in Africa and Western capitals of more attacks by jihadi militants.
"Strategically what those extremists want is to expand the operation in other areas, in neighbouring countries to divert attention from northern Mali," Abdulaziz said.
The Mali crisis and the response by African countries and Western states is likely to dominate the AU summit being held in the Ethiopian capital, Addis Ababa.
Any U.N. peacekeeping force would need to be drawn from neighbouring countries, Abdulaziz said.
"You can't secure an area without its own people and therefore the engagement of neighbouring countries in a peacekeeping operation is a must," he said.
There is, though, much combat to be fought before peacekeepers could be deployed.
Strikes by French jets and helicopter gunships on militants in rebel held Malian towns have halted their southern advance and forced them to surrender some towns in the country's north.
An African force comprised mostly of units from the West African regional grouping ECOWAS, is readying for deployment. It is expected to number more than 5,000 soldiers.
But questions remain whether they will have the weapons, equipment and training needed to sustain a campaign against rebels in remote desert and mountain terrain the size of Texas.
(Writing by Richard Lough; Editing by Jon Boyle)