The Food and Drug Administration announced on Tuesday that for the first time it had begun exercising its power to regulate cigarettes and other tobacco products, an authority it was given under a 2009 law supported by President Obama.

Agency officials said they had authorized the sale of two new products — both of them Newport cigarettes made by the Lorillard Tobacco Company — and rejected four others. The law forbade them to name the rejected products, they said.

Before the law, cigarettes were manufactured without any federal regulation. Instead, states decided where and how tobacco products would be sold, but had no authority over the ingredients they contained. Now, the F.D.A. is deciding which new products can be sold. In addition to cigarettes, the agency’s authority covers loose rolling tobacco, chewing tobacco and snuff.

The agency can reject cigarettes and other tobacco products that its scientists believe pose public health risks above and beyond comparable products already on the market, a sharp departure from past practice, when tobacco companies could change existing products and introduce new ones at will.