The Ministry of Agriculture in Greece on Monday banned the transport of sheep and goats across the country after a highly contagious plague appeared in many areas following the outbreak on July 11.
The outbreak, which officials linked to imported livestock, has sickened thousands of animals in the neighboring country, with nearly 10,000 destined for slaughter.
"The movement of sheep and goats for breeding and slaughter is prohibited throughout the country," the Greek ministry said in a statement.
Authorities said its veterinarians had found cases of sheep and goat plague in the regions of Corinth and Larissa after tracing "the route followed by animals imported from a certain country".
Later on Monday, another case was found in the greater Athens area west of the capital, Deputy Agriculture Minister Christos Kellas told state broadcaster ERT, bringing the total number of affected animals to more than a dozen.
The sick animals were located before symptoms of the disease appeared, the Greek ministry said.
Officials did not name where the animals were imported from.
But the ministry has already said that Greece mainly imports sheep and goats from Turkey, Albania and Romania.
Romanian officials declared an outbreak of the disease on July 19, eight days after the first cases appeared on a farm in Baia near the Black Sea coast.
By July 26, the virus had spread to several Romanian farms, while Romanian authorities have slaughtered around 58,000 sheep and goats.
"If they came from Romania, they entered freely," Kellas told Skai TV.
"Animals are not checked at the border [when entering] from an EU country," he said, adding that Romania had not declared an outbreak before the first cases in Greece.
More than 9,000 animals have been identified for culling, including 7,000 already killed in central Greece after the disease appeared near the town of Kalabaka on July 11.
Kellas called Greece's response to the outbreak "the largest veterinary operation ever carried out in the country".
Last week, a top veterinary official in the area was fired after it emerged that some of the sheep had been buried alive, the local Greek governor said.
The disease, known as Peste des Petits Ruminants (PPR), is highly contagious to sheep and goats but does not affect humans. Pasteurized meat and milk are also safe to consume, officials said.
The Greek Ministry of Agriculture has said that it is the first time that the disease has been detected in the country.
Greek farmers increased livestock imports after local herds were decimated in last year's catastrophic floods caused by Storm Daniel, when tens of thousands of sheep perished.