Unless urgent action is taken, as many as 1 billion people this century -- more than two-thirds in the developing world -- could die from tobacco-caused illnesses, Bloomberg and Gates said.

Bloomberg's Initiative to Reduce Tobacco Use, which includes a $125 million commitment, will be extended with a new $250 million, four-year commitment. Bloomberg's total anti-tobacco commitment is more than $375 million.

The Bill & Melinda Gates Foundation announced it will invest $125 million over five years to fight tobacco, including a $24 million grant to the Bloomberg Initiative. In addition, the Gates Foundation will support complementary efforts to reduce high rates of tobacco use in countries such as China and India, as well as to help prevent the spread of tobacco from taking root in Africa.

"Our commitments will help governments confront the tobacco epidemic by implementing the (World Health Organization's) proven MPOWER package," Bloomberg said in a statement.

"This means assuring well-staffed tobacco control programs, raising tobacco taxes, running hard-hitting public information campaigns, creating comprehensive smoke-free public places and banning tobacco advertising."