LONDON (Reuters) - Britain on Tuesday boosted its offer of aid to help France fight Islamist rebels in Mali, and pledged troops to help other African governments in the region counter a rising tide of Islamist radicalism.

Up to 240 British troops could be deployed as part of two missions to train African troops, 40 in Mali as part of a European Union mission, and a further 200 in anglophone West African countries, Prime Minister David Cameron's spokesman said.

At least 70 more British personnel could be involved in logistical and support missions. "It is an African operation in support of the Malian government and we think that the right way to do this is for regionally-led forces to take the lead," the spokesman said, adding Britons would take no combat role.

The increased logistical support for France includes a ferry to transport troops and equipment to Africa, and allowing France and its allies to use Britain for air-to-air refueling.

Britain has also offered to set up a "Combined Joint Logistics Headquarters" in Mali, but France believes such a facility is not needed, Cameron's spokesman said, adding it would be kept under review.

A decision on whether to send up to 200 British soldiers on West African training missions is expected to be taken soon after African Union-led discussions in Addis Ababa, while talks are taking place in Brussels over troops for Mali.

(Reporting by Mohammed Abbas; Editing by Andrew Osborn)