.France has become the latest country to increase airport security in line with a request from Washington to enhance screening for flights to the US.

On Wednesday the US warned of a "credible" terrorism risk to international flights, without revealing the specifics of the threat.

The UK and Germany are among those who have complied with the request.

On Thursday security was increased in Uganda's capital Kampala following a "specific threat" to its airport.

France's civil aviation authority, DGAC, said the enhanced screening "will be carried out in a way to limit as much as possible inconvenience to passengers".

It warned however that "delays are possible".

A DGAC spokesman said "we cannot divulge the added measures" being taken.

Dozens of direct flights from France to the US are believed to be affected. Officials are recommending passengers arrive at airports early to allow time for screening.

On Thursday the UK said that it too would increase checks because of an "evolving threat" but said people should travel as usual.

A US Department of Homeland Security (DHS) official said on Wednesday the requests were in response to a "real-time" and "credible" threat, but that he could not comment on specific intelligence matters.