Britain is prepared to take the risk of sending a "sizeable amount" of troops to Mali and neighbouring West African countries as David Cameron offers strong support to France in its operation to drive Islamist militants from its former colony.

As news emerged that insurgents retreating from Timbuktu had set fire to a library containing thousands of priceless historic manuscripts, Downing Street said the prime minister told François Hollande on Sunday night Britain was "keen" to provide further military assistance to France.

Cameron despatched Sir Kim Darroch, his national security adviser, to Paris on Monday to discuss what help Britain could provide. Government sources said decisions on troop deployments were expected to be made in the coming days as France confirms its exact requirements. One source said that Britain could easily dispatch 200 troops if France requested such a number.

Britain is prepared to provide hundreds of troops to help the operation and is considering a few options:

• Forming part of an EU military training mission in Mali. The British contribution to this would be in the "tens", according to Downing Street.

• Training troops from the Economic Community of West African States (Ecowas) in neighbouring countries for possible operations on Mali. This is likely to be the main focus of Britain's contribution because Ecowas members include many countries with strong links to Britain. British troops could be used to train Nigerian forces.

• Providing "force protection" for the trainers. This would be armed protection but would not amount to a combat role.

Downing Street is adamant that British troops will play no part in combat. A spokesman said: "We have the capability and capacity to do that. We have the ability to contribute a sizeable amount if required."

Britain initially put two RAF C17 transporter aircraft at the disposal of France for the transport of troops and material to Mali. One of these is still dedicated to the Mali mission.

Britain has also sent one RAF Sentinel surveillance and reconnaissance aircraft to Senegal to help with the mission. The Guardian reported last week that a small number of British special forces soldiers were on the ground in Mali advising the French.

The help from Britain came as the mayor of Timbuktu spoke of a "devastating blow" to world heritage after insurgents torched two buildings that held the city's manuscripts, some of which dated back to the 13th century. The manuscripts that survived the fire were reportedly taken away by the rebels.

Hallé Ousmani Cissé said al-Qaida-allied fighters on Saturday also burned down the town hall, the governor's office and an MP's residence, and shot dead a man who was celebrating the arrival of the French military.

French troops and the Malian army reached the gates of Timbuktu on Saturday and secured the town's airport. But they appear to have got there too late to rescue the leather-bound manuscripts that were a unique record of sub-Saharan Africa's rich medieval history. The rebels attacked the airport on Sunday, the mayor said.

"This is terrible news," Cissé said. "The manuscripts were a part not only of Mali's heritage but the world's heritage. By destroying them they threaten the world. We have to kill all of the rebels in the north."

On Monday French army officers said French-led forces had entered Timbuktu and secured the town without a shot being fired. A team of French paratroopers crept into the town by moonlight, advancing from the airport, they said. Residents took to the streets to celebrate.

Downing Street said Cameron made his offer of further help in a telephone call with Hollande on Sunday evening.

The spokesman said: "On Mali the French president gave an update on the progress that Mali and French forces have been making. He also thanked the prime minister for the transport assistance which the UK has provided.

"The prime minister made clear that we fully support the French government's actions working with the Malian government at their request to deny terrorists a safe haven in Mali. The prime minister went on to explain that we are keen to continue to provide further assistance where we can, depending on what French requirements there may be.

"With regard to that, the UK national security adviser is in Paris today for discussions with French authorities on what further assistance we may be able to provide to them."

The spokesman said Britain's position on having no combat role in Mali remained "absolutely unchanged". But he said No 10 was prepared to provide more help "around logistics, intelligence and surveillance support".

He added: "It is very much discussing about what more we may be able to do, subject to requests from the French government. We very strongly support the French intervention. If there is more we can do we are keen to do what we can to help within the sphere of what the prime minister set out very clearly previously in the House [of Commons]."