Havana, Cuba—Cuba is far from seeing a McDonald's or Starbucks open any time soon, but the diplomatic thaw with the United States is bringing more American visitors to the sweltering island.

While the US embargo against Havana still forbids regular tourism to Americans, a growing number have flocked to the Caribbean destination under easier-to-get special permits.

Excitement about visiting Cuba has grown since US President Barack Obama and Cuban counterpart Raul Castro made the shock announcement in December that they would restore diplomatic relations.

While the two countries have yet to reopen their mutual embassies, Obama and Castro will take a new step in the warming relations with a possible historic meeting at the Summit of the Americans in Panama this week.

Cuba has fascinated tourists from around the world because it appears frozen in time, with its aging buildings and old Buicks from the 1950s that are still around as the embargo prohibits imports of US cars.

"Cuba is in fashion in the US because people don't know about it, they're curious because we think it's like being back to life 50 years ago," said Walton, a retired professor from New Jersey who walked along Old Havana with a tour group.

Walton and his group were visiting Cuba under an education license, one of the 12 categories permitted by US authorities. The others include cultural, religious, artistic and sporting visits.

"People in the US feel that as soon as it opens up more ... there will be more an more tourists," said Larry, a visitor from California.

"It's wonderful, the climate is great, everything is fine," said Larry, admiring Havana's National Capitol, whose design took inspiration from the US Congress.

- Easier to visit -

US-based companies that organize visits say demand has soared this year. In January, Obama made travel under the special categories a bit easier by no longer requiring that US visitors ask for permission before getting on a plane to Cuba.

"The measures ... that we have softly implemented  have achieved what we wanted, which is to increase contact among US and Cuban citizens," Ricardo Zuniga, Obama's top Latin America advisor, told reporters in Washington on Tuesday.

Recalling that Obama urged Congress to lift the embargo in January, he said, "we think that it's through dialogue and contact we will be able to see an improvement in the conditions of Cuban citizens."

Tom Popper, president of tour company InsightCuba, said his firm sends 3,000 to 5,000 Americans to Cuba per year but hopes to double or triple that figure this year.

"Cuba and traveling to Cuba is on the mind of most Americans," said Popper, whose New York-based company organized visits last year by Major League Baseball legends Ken Griffey Jr. and Barry Larkin.

Alina Fernandez, president of Cuba Travel USA, said interest has quadrupled for the next high season, which is between December and May.

Some 100,000 Americans visit Cuba every year, a figure that could rise by 30 to 50 percent this year, Fernandez said. The problem, she said, is that the country lacks the hotel capacity for a major tourism influx.

The warming US-Cuba ties has raised hopes among Cubans that the rapprochement will be coupled with renewed business between the two countries, bringing more money to a country where people make $20 per month on average.

"The American tourist is the best in the world. Americans are splendid when it comes to tipping. We've had many here in the past months," said Victor Hugo Felipe, owner of the Kilometro 0 restaurant, one of the private "paladares" that have opened in recent years.

- Fear of McDonald's everywhere -

The US-Cuba detente appears to have also had an impact on tourism from other countries.

Cuba's government says three million tourists from around the world visited the island last year.

But a record-shattering one million came just in the first quarter of this year -- a 14 percent increase from the same period last year.

The surge has been fueled by traditional visitors from Canada, Germany, France, Britain and Italy, but the tourism ministry has also registered a 29.5 percent increase in American visitors.

Johan Dorssemont, director of the Havana office of Belgian travel agency Transnico Internacional, said the increase in tourism can be attributed to a new marketing message among tour operators in Europe: "If Americans come, everything will change, they'll put a McDonald's anywhere they want."

"Tourists want to come now to see Cuba because it's different" from other destinations, Dorssemont said.