Britain urged travellers to leave Georgia as soon as possible Sunday, after the explosion of violence between the ex-Soviet country and Russia, the AFP reported.
Bolstering its travel warning for the second day in a row, the Foreign Office said "if you have no urgent need to stay in Georgia, you should leave as soon as possible."
"It is wise to do so while some air services are still available and the border remains open," it added.
On Saturday the Foreign Office had advised Britons against all unnecessary travel to Georgia, after the pro-Western country declared a state of war with Russia over the separatist region of South Ossetia.
On Sunday it reiterated that advice as well as warning against all travel to South Ossetia, Abkhazia and the upper Kodori Valley, also known as upper Abkhazia.
"Serious fighting continues in the conflict zone of South Ossetia," it said, adding that there had been aerial bombardments of Georgian military bases in the Black Sea port of Poti, as well as Vaziani, Senaki and Marneuli.
The situation in Georgia remained unclear Sunday after Russia sent in tanks and troops in response to Georgia's military offensive to take back South Ossetia, which broke away in the early 1990s.
Georgia said 10,000 more Russian troops had entered the country and Russian warships set up a sea blockade of its smaller neighbour, according to the Interfax news agency.
But a key official said Georgian forces had withdrawn from nearly all of South Ossetia "as an expression of good will and our willingness to stop military confrontation."