BERLIN, July 3 (Reuters) - The health ministry in the German state of Thuringia said on Tuesday the lethal H5N1 strain of avian flu had been confirmed in a wild bird.

The Friedrich Loeffler Institute had identified the H5N1 strain in a black-throated diver, the ministry said in a statement, adding that a suspect swan was also being tested, with results expected on Wednesday.

A three-km (two-mile) restricted zone had been set up around the area where the infected diver was found and all poultry within the zone would have to be confined to stalls, it said.

An observation zone with a 10-km (six-mile) radius had also been established, it added.

Germany has found the virus in several wild birds in the eastern state of Saxony and southern state of Bavaria, while the Czech Republic has reported finding it at two poultry farms and in a dead swan.

Officials at Germany"e;s top state veterinary laboratory said last week the strains were similar in the two countries and probably had a common source.

Last year, about 13 European Union member states confirmed cases of bird flu. The virus has been spreading across southeast Asia, killing two people in Vietnam last month, the first deaths there since 2005.

Globally, the H5N1 virus has killed nearly 200 people out of over 300 known cases, according to the World Health Organisation. None of the victims were from Europe.