Britain is sending up to 330 military personnel to help train a West African intervention force in Mali, Downing Street has said.
The move was announced a day after David Cameron assured French President Francois Hollande he was "keen" to assist operations against Islamist fighters in the former colony.
On Tuesday, Downing Street also confirmed that the UK would offering up to 40 troops as part of EU training mission in Mali.
Britain has also offered a roll-on roll-off ferry to help transport equipment to the French force in Mali, the Number 10 spokesman added.
The offer of assistance came after the prime minister told Francois Hollande on Sunday night that Britain fully supports the French government's actions, "to deny terrorists a safe haven in Mali".
The soldiers could be sent to assist with logistics, surveillance, intelligence and transport alongside the proposed EU mission to train the Malian army.
Downing Street has insisted that troops would not be involved in combat.
Cameron and Hollande spoke earlier this week as French troops secured the key city of Timbuktu.
As insurgents retreated, they set fire to a library containing precious manuscripts thousands of years old, according to reports.
Cameron's official spokesman outlined the PM's phone call with Hollande to reporters last night, saying: "The French president gave an update on the progress that French and Malian forces have been making and also thanked the prime minister for the UK transport assistance.
"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 UK is offering:
- 200 personel for training in West Africa countries.
- 40 troops as part of EU training mission in Mali, but not for force protection.
- The use of a "strategic roll on roll off" ferry to take French equipment from France to Africa.
- A joint logistics HQ in Mali but France said it did not need it at this time.
- The extended the use of one C17 transport plane by three months.
- Allowing "allies" to fly air-to-air refuelling jets out of Britain.
"The prime minister went on to explain that we are keen to continue to provide further assistance where we can, and depending on what French requirements there may be.
The RAF has already provided two heavy-lift C17 transport planes and a Sentinel surveillance aircraft to assist France's operation, and National Security Adviser Sir Kim Darroch has been sent to Paris to discuss what further help may be offered.
Lindsay German from Stop The War Coalition told the Huffington Post UK she feared British intervention in the conflict may escalate even further.
She said: "We fear intervention may escalate to much higher levels, dragging in more and more troops.
"That’s what happened in Vietnam; it started off with advisors being sent and then turned into full blown war. We’re not saying what happened in Vietnam is happening here, but intervention could escalate in the same way. "
Shadow Defence Secretary Jim Murphy said it was important the government made it clear what role Britain was playing in the conflict.
He told the Mirror: "We support the mission in Mali but it's important the government keeps the public and parliament informed about all major decisions so there is clarity about British aims in the region."
Meanwhile Bernard-Henri Levy, one of France's best known philosopher's and a champion for intervention in conflict zones, has described the British response to the Mali crisis as "spineless".
"The English airplanes were with the French airplanes to liberate Libya. Where are they today when we need to liberate Mali and stop the creation of a Jihadist state on Europe’s doorstep?" he was quoted as saying.
Former head of the Army General Sir Mike Jackson backed the government's position but warned that nations involved may face a "protracted guerrilla warfare".
"It doesn't really surprise me that the British government feels it needs to be seen to be helping," he told the BBC Radio 4 Today programme.
"We cannot let states fail because we know from recent history that failed states just lead to really difficult circumstances, instability."
He added: "What Mali and France, and indeed other countries who may choose to assist may face, of course, is a protracted guerrilla warfare taking place away from the conurbations."