WASHINGTON — The U.S. government on Thursday tentatively approved scheduled commercial airline service to Havana from 10 American cities, further bridging the gulf between countries as close as 90 miles and an hour flight but long kept at a greater distance by the Cold War.

The decision is another long stride in President Barack Obama's effort to normalize relations between the United States and Cuba.

“Reopening travel relations with Cuba is about more than just restoring the freedom to travel there for all Americans — it's about opening Cuba to new ideas, new values and improved human rights that our 50-year-old policy of isolation could not achieve,” Sen. Dick Durbin, D-Ill., said.

Mark Feierstein, senior director at the National Security Council for Western Hemisphere affairs, said Obama believes the American people “are the best ambassadors for democratic values.”

Eight U.S. airlines are expected to begin round-trip service as early as this fall, Transportation Secretary Anthony Foxx said.

The U.S. cities are: Atlanta, Charlotte, N.C., Houston, Los Angeles, Newark, N.J., New York and four in Florida — Fort Lauderdale, Miami, Orlando and Tampa. Of the 20 daily nonstop flights allowed to Havana, 14 are from Florida, home to the largest population of Cuban Americans.

The airlines are Alaska, American, Delta, Frontier, JetBlue, Southwest, Spirit and United.

A year and a half ago, Obama announced with Cuban President Raul Castro that it was time for the longtime adversaries to “begin a new journey.” Washington has since reopened the U.S. Embassy in Havana and taken other steps to bolster ties.

Conservatives in Congress have been unwilling to lift the trade embargo of Cuba, which includes a travel ban. That means most Americans still cannot legally visit Cuba. But the administration has eased rules to the point where travelers are free to design their own “people-to-people” cultural exchange tours with little oversight.

Cuban Americans have been able to travel to Cuba without restriction since 2009.

Airlines still need to record — and keep for five years — the official reason why someone travels to Cuba, so reservation systems have been revamped to allow passengers to select one of the 12 permitted categories. They include family visits, official business, educational or religious activities.

Foxx said the decision won't be final until later this summer in order to provide a 30-day public comment period.

Last month, the Transportation Department announced the approval of six U.S. airlines to begin service as early as this fall to other Cuban cities.

The government's decision, if made final, would require that the airlines begin service within 90 days of the issue date of a final order.

U.S. citizens' interest in visiting Cuba has swelled since relations between the two nations started to thaw in December 2014.