Iran’s president-elect, the moderate cleric Hassan Rouhani, has promised to support the country’s largely untapped tourism sector, but the arrest of European tourists this spring has cast a shadow over that effort.

Rouhani has been adamant about the importance of tourism to Iran’s economic growth, and since being elected he has set a goal of more than doubling, to 10 million, the number of foreigners who visit Iran each year. Such an increase, over the current level of 4 million tourists, would “create jobs for 4 million people, solving the problem of 3.5 million unemployed people in this country,” Rouhani has said.

On Kish, an island in the Persian Gulf just off Iran’s mainland that is a favorite domestic destination of Iranians, developers have been waiting for years for an administration that is serious about tapping the country’s tourism potential.

The island is home to dozens of high-end construction projects, including hotels and shopping malls, and already attracts more than a million visitors each year. As at other Iranian tourist destinations, however, visitors are overwhelmingly Iranian.

“We have to prepare the infrastructure and plan for an increase of tourists. It will take at least a decade for us to become an international destination,” said Mahan Modaven, a marketing consultant for the Kish branch of Iran’s Tourism Ministry.

In accounting for the country’s relatively low number of visitors, Rouhani blames sanctions, specifically those that have made it difficult, if not impossible, for tourists to use international credit and ATM cards. But tourism experts here think the problems run much deeper.

They say authorities’ general suspicion of foreigners and a lack of tolerance are the major obstacles preventing Iran from taking a larger slice of international tourism revenue, despite the country’s many environmental and historical attractions.

“We have all the potentials that we need to attract foreign tourists, but due to limitations, mostly cultural, like Islamic hijab, they do not come here. To attract them, we need to create a better political and social atmosphere,” said Ramezan Gholinejad, an organizer of the annual Kish Summer Festival.

Slovak tourists arrested

One field in which Iran hopes to gain ground is adventure travel, but news of the arrest more than a month ago of Slovak paragliders who entered Iran legally with tourist visas highlights just how far Iran might be from becoming a serious international destination.

The Slovaks, along with their local host, a well-known member of Iran’s paragliding community, were arrested after flying over a military installation days before Iran’s presidential election.

“They came to Iran as tourists but behaved inappropriately and had unconventional devices in their possession. They broke the laws of the Islamic Republic of Iran and were arrested by the relevant authorities,” Foreign Ministry spokesman Abbas Araqchi told the Iranian Students’ News Agency on June 30.

Because of its high mountains, good wind conditions and low prices, Iran has become a favorite destination for European paragliders, and the site where the Slovaks were arrested was a front-runner to host an upcoming international paragliding competition, according to Mohammad Razeghi, the head of Iran’s air sports association.

The arrests could cause other potential visitors to rethink their travel plans, even though, Razeghi said, “the only problem that led to their arrest was not having proper permission to fly.’’

Despite enduring perceptions of Iran as unsafe, the country experienced a 25 percent increase in foreign tourist arrivals in 2012 compared with the previous year, according to Manoucher Jahanina, Iran’s deputy tourism minister. The 4 million foreign visitors produced more than $8 billion in tourism revenue, he said.

But some in the field say that any spike in tourism has more to do with factors beyond authorities’ control than active development and promotion.

Arash Nooraghayee, head of the Tour Leaders Association of Tehran and an analyst of Iran’s tourism industry, said he believes that the country may be benefiting principally from a devaluation of its currency and the fact that other regional destinations, including Egypt, Syria and Turkey, have experienced intense conflict.

“We should be seeing feedback in the form of more investment in the tourism sector, and that isn’t really happening yet,” Nooraghayee said.

The potential is there

On Kish, investment continues, but foreign tourists are still a rarity.

In the steamy heat that soars well past 100 degrees at this time of year, Kish’s 16th annual Summer Festival is in full swing, with daily concerts and dance shows at sunset next to the island’s top tourist attraction, the Greek Ship, a rusting cargo vessel that was stranded just off the island’s shore in 1966.

For just over a dollar per ride, a speedboat delights passengers by circling dangerously close to the wreck. Camel and horse rides are also available. Kurdish men dressed in their trademark baggy pants dance to traditional music, and enormous tortoises swim just beneath the water’s surface, periodically coming up for air to a sea of waiting flashbulbs.

Tourism-industry professionals here sense the possibility, but they are clearly aware of the limitations.

“Rouhani’s team are technocrats and look at tourism as a major industry with a lot of potential. I am very hopeful they can make progress in Iran’s tourism,” said Gholinejad, the festival organizer. “If this industry grows, everyone will benefit from it, especially in terms of job creation.”

But Iran’s strict Islamic regulations continue to be a major impediment to attracting foreign visitors. Even scuba diving is affected by religious restrictions that require unmarried tourists to be segregated by gender.

Kish is surrounded by coral reefs teeming with tropical fish, and a single dive on the island costs approximately one-fifth of what it does in Dubai, about 100 miles away on the other side of the gulf. But Ghasem Nargesi, an instructor at the Kish Diving Center, said demand remains tepid.

“We have the capacity to handle 3,600 divers per year,” Nar­gesi said, “but some weeks, we only get one client.’’