HAMBURG, July 4 (Reuters) - More wild birds have tested positive in Germany for the lethal H5N1 strain of bird flu, German authorities said on Wednesday.

Two wild birds tested positive for H5N1 in the eastern state of Thueringen. About 100 birds of various types were found dead in the state and about 40 were being tested for bird flu, Germany"e;s Friedrich-Loeffler national animal diseases institute said.

Last week, Germany discovered H5N1 in Leipzig in the eastern state of Saxony and in the southern city of Nuremberg in cases involving a total of nine wild birds.

The source of the outbreaks, the first in Germany in 2007, was unclear.

French authorities also said on Tuesday they were investigating possible cases of bird flu in wild birds.

Last year, 13 European Union member states had confirmed cases of bird flu -- Germany, Austria, Denmark, Italy, Greece, Britain, the Czech Republic, Poland, Slovakia, Slovenia, Sweden, France and Hungary.

Bird flu has been spreading across southeast Asia and killed two people in Vietnam this month, the first deaths there since 2005.

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