TEHRAN, Iran -- Iran's vice-president told The Associated Press on Sunday his country is preparing for a "tsunami" of foreign tourists as Iran and world powers are set to begin implementing a landmark nuclear deal that will lift sanctions in return for curbs on Iran's nuclear program.

Masoud Soltanifar, who is also Iran's Cultural Heritage, Handicrafts and Tourism Organization chief, said President Hassan Rouhani's moderate policies and the easing of visa rules are opening the door for the return of foreign tourists to Iran.

A country rich in historical and cultural treasures, Iran will unveil an investment package of 1,300 projects in the coming days to attract foreign investment and boost the badly-hit tourism industry. Iran is home to 19 UNESCO-registered sites.

Even before sanctions are lifted, the number of foreigners visiting Iran has grown 12 per cent in each of the past two years. In 2014, Iran hosted over 5 million tourists, bringing in some $7.5 billion in revenue.

About half were Shiite Muslims, the same religious denomination as most Iranians, and the other half were tourists from Europe, North America and east Asia.

"In the post-sanctions era, tourism is an industry that will get a boost more than any other sector," Soltanifar told the AP. "Tourism is certainly the driving engine to get Iran's economy out of recession. Iran's tourism sector is a flourishing market for investors. We are anticipating a tsunami of tourists after sanctions are lifted."

But the U.S. State Department warns U.S. travellers to "carefully consider the risks of travel to Iran," advising Americans with dual Iranian citizenship in particular that they may encounter difficulty leaving the country. It says U.S. citizens may be subject to harassment or arrest while travelling in the country.

The country's Revolutionary Court has convicted Washington Post reporter Jason Rezaian on charges including espionage without providing details on the verdict or sentence. Rezaian, who was detained in July 2014, has now been held longer than the 52 American diplomats and citizens who were held hostage in Iran for 444 days from late 1979 to early 1981.

Besides Rezaian, former Marine Amir Hekmati, who holds dual Iranian and American citizenship, was arrested in August 2011.

The U.S. has also asked for the Iranian government's assistance in finding former FBI agent Robert Levinson, who went missing in 2007 while working for the CIA on an unapproved intelligence mission.

Soltanifar, a member of Rouhani's Cabinet, said officials are trying to remove obstacles for tourists and issue visas on arrival at the airport in Tehran for nationals of 190 countries. They will be valid for 30 days, with the possibility of extending for another 15 days. Tourism authorities are also planning to issue electronic visas beginning next year, he said.

Americans and Brits travelling to Iran will need a visa ahead of time to enter mainland Iran, according to their respective governments. In 2014, there were 3,400 American visitors to Iran, up from 1,800 in 2013, Soltanifar said.

Iran aims to host 20 million tourists a year by 2025, with expectations of growing the tourist industry to $30 billion.

Currently, Iran lacks sufficient accommodation and transportation for that number of tourists. Iran has 1,100 hotels and guest houses, 130 of them 4 and 5 star hotels.

"We need to increase our four and five star hotels from 130 to 400 in 10 years. We are providing low-interest funds out of the National Development Fund to private investors to build modern hotels," Soltanifar said.

Iran needs more than 400 new passenger planes to compensate for shortages due to sanctions over the past three decades. Of its 250 passenger planes, 100 are currently grounded because of lack of spare parts. The remaining 150 aging aircraft need to be renovated.

"We need to renovate our air transportation system and buy new planes after sanctions are lifted. But this will be time-consuming," he added.

Iran has a history of air crashes in recent years, leading to hundreds of casualties. Last week, an Iranian passenger plane safely landed after part of an engine fell off during a flight with 426 passengers and crew members aboard.

Iran's constitutional watchdog, the Guardian Council, ratified into law this week a parliamentary bill implementing the landmark nuclear deal with world powers. The UN Security Council previously approved the deal on July 20 and U.S. Congress blocked efforts by Republicans to derail the accord in September.

Soltanifar, a moderate politician, welcomed investors and tourists from the U.S., known by hardliners as the "Great Satan."

"American tourists and investors are welcome. There is no obstacle or restrictions for them to visit Iran or invest in the country," he said.

France and the United Kingdom have relaxed travel advice for their citizens following the historic July nuclear deal. The U.K. reopened its embassy in Tehran in August after a four-year closure.

Last month, an Iranian firm signed an agreement with French hotel giant AccorHotels to use the Novotel and ibis brands for 15 years, the first deal of its kind in three decades.