ROME, May 2 (Reuters) - A new strain of foot and mouth disease (FMD) has reached the Gaza Strip and threatens to spread further after first being detected in Egypt and Libya in February, the United Nations' Food and Agriculture Organisation (FAO) said on Wednesday.

FAO said sick animals had been detected on April 19 in Rafah, a town that lies on the border between the coastal Palestinian territory and Egypt.

FMD is a highly infectious and sometimes fatal disease that affects cloven-hoofed animals such as sheep, goats, cattle, buffalo and pigs. It is not a direct threat to humans.

An official in Gaza's ministry of agriculture said farmers had received 20,000 doses of vaccine to fight the disease and played down the seriousness of the outbreak.

"The problem surfaced at one farm in Rafah and we isolated the farm and stopped the movement of animals across Gaza," Adel Attalah told Reuters.

"We received the 20,000 vaccines a week ago and ... I can say that most of the animals were given the vaccine," he said, adding that his ministry had now lifted restrictions on the movement of animals. "The situation is not worrying," he said.

Meat and milk from sick animals are unsafe for consumption, not because FMD affects humans, but because foodstuffs entering the food chain should only come from animals that are known to be healthy, FAO said.

Movements of animals from the Nile Delta eastward through the Sinai Peninsula and north into the Gaza strip have been deemed the highest risk for the spread of the disease into the wider Middle East region, the Rome-based agency said.

"If FMD SAT2 reaches deeper into the Middle East it could spread throughout vast areas, threatening the Gulf countries - even southern and eastern Europe, and perhaps beyond" said Juan Lubroth, FAO's Chief Veterinary Officer.

The FMD virus is transmitted via the saliva of sick animals, and spreads easily via contaminated hay, stalls, trucks and clothing, FAO said.