HAVANA - The popular online home-rental service Airbnb started allowing American travelers to book lodging in Cuba on Thursday in the most significant U.S. business expansion on the island since the declaration of detente between the two countries late last year.

For a half-century, the U.S. trade embargo had blocked such businesses from entering the Cuban market. In January, however, the Obama administration loosened a series of restrictions on U.S. business in an attempt to encourage the growth of the island's small private sector.

Airbnb searches for "Cuba" now turn up more than 1,000 properties across the island, with 40 percent in Havana and the rest in tourist destinations such as Cienfuegos, a few hours away on the southern coast. The company has been sending teams of representatives to Cuba for three months to sign up home owners, and plans to expand steadily in coming months.

"We believe that Cuba could become one of Airbnb's biggest markets in Latin America," said Kay Kuehne, regional director for Airbnb, the website and mobile app that allows users to book rooms in more than a million private homes around the world.