BUCHAREST, Dec 8 (Reuters) - New suspected cases of bird flu have been found in southeast Romania, close to the Danube delta where the deadly strain of the virus was first detected in October, officials said on Thursday.

Avian flu has since been found in a dozen villages in and around the delta, which is Europe′s largest wetland and lies on a major migratory route for wild birds.

"Preliminary tests on hens in three chicken farms in the village of Zavoaia in Braila county showed that it is possible that they have bird flu," Gabriel Predoi, an official from Romania′s Animal Health Agency, told Reuters.

"But we have to run more detailed tests to see whether it is indeed bird flu."

Three outbreaks have been confirmed as the highly pathogenic H5N1 strain which has killed 69 people in Asia. Samples from other outbreaks are still being examined in Britain but officials say it is likely that they are of the same strain.

The three chicken farms in Zavoaia, which is near two other villages in Braila county where bird flu was discovered last week, have been quarantined.

Disinfection checkpoints have been installed on all roads out of the county.

Officials warned that high temperatures for this time of the year mean the peak migration period for wild birds would be longer, increasing contamination risks, and told villagers to keep domestic birds isolated.

The Danube delta on the Black Sea lies on a route millions of wild birds use to migrate towards warmer winter climates in North Africa.

Neighbouring Ukraine began culling birds at the weekend after finding avian flu in the Crimean peninsula.

Scientists fear H5N1 could mutate into a form that spreads easily among humans and that millions could die in a pandemic. So far there is no sign the virus has changed in this way.

Romania has reported no cases of bird flu in humans so far.