SAO PAULO - SAO Paulo state officials have launched what they say is Latin America's first passenger bus with an electric engine powered by hydrogen fuel cells.

Governor Jose Serra says the bus will start test runs on the streets of South America's biggest city in August and will be joined by three similarly powered vehicles next year.

In a fuel cell, hydrogen reacts with oxygen to produce electricity and water.

'Brazil is one of five countries in the world that have mastered this technology and that has developed a hydrogen-powered bus,' Mr Serra said at Wednesday's launching ceremony. Among the others are the US and China.

The state government has not provided information regarding investment or future production plans. -- AP