UPDATE 1-China's Buffett-backed BYD to build buses in Bulgaria

SHANGHAI, Dec 12 (Reuters) - BYD Co Ltd , the Chinese carmaker backed by billionaire investor Warren Buffett, said on Wednesday that it would launch a joint venture in Bulgaria to produce electric buses, marking its first assembly plant overseas.

The move is the latest by a Chinese automaker to expand abroad into emerging markets including Southeast Asia and India.

A BYD spokeswoman declined to disclose investment details about the 50-50 joint venture with Bulgarian energy firm Bulmineral, which will be based in Breznik, a small town about 50 km (30 miles) west of Sofia.

The venture will be named Auto Group Motors and is expected to deliver its first sample electric bus in February 2013, the official Xinhua news agency quoted Bulmineral Chief Executive Alexander Usachev as saying.

The plant will produce 40 to 60 buses a month when it is operating at full capacity, Usachev said without elaborating.

The joint venture will also produce other BYD products, such as batteries and LED light bulbs, the Xinhua report said.

BYD has been promoting its electric vehicles in countries such as the Netherlands, Finland, Denmark, Canada, Uruguay and the United States.

Electric buses made at its Bulgaria plant will be sold locally first and in neighbouring countries in the future, the BYD spokeswoman said.

Last week, China's biggest carmaker SAIC Motor Corp said it was planning to form a venture in Thailand with local firm C.P. Group Co Ltd.

Great Wall Motor Co is in talks to open a plant in India, an official at an Indian lobby group said on Monday, a move that would make it the first Chinese carmaker to operate in the country without a partner.