Iran are scheduled to play all three World Cup group matches in the United States, but the team's participation in the June 11th to July 19th tournament has been in question since the US and Israel attacked Iran in late February.
More questions arose after FFIRI President Mehdi Taj was refused entry to Canada for the FIFA Congress in Vancouver earlier this month because of his links to the Islamic Revolutionary Guard Corps (IRGC).
Both the US and Canada, who are co-hosting the World Cup with Mexico, classify the IRGC as a 'terrorist entity' and have made it clear they will not admit people with links to the elite military force.
Kazem Gharibabadi, Iran's Deputy Foreign Minister for Legal and International Affairs, said in a social media post this week that it was incumbent on FIFA to ensure that all teams and their delegations were able to get into the host countries.
"The Iranian national football team has earned its right to participate on the field in accordance with FIFA regulations," he wrote.
"Any obstruction to the entry of players, technical staff, federation officials, or essential members of the Iranian delegation would violate the spirit and purpose of the World Cup...
"If the organising body cannot guarantee that all qualified teams, including Iran, can enter the host country without discrimination or restriction and compete on equal terms, the credibility of the World Cup itself will be damaged."
The source said FIFA was working closely with the relevant authorities to ensure all teams at the World Cup were able to compete in a safe and secure environment.
US President Donald Trump said two weeks ago that he was "okay" with Iran playing at the World Cup despite the conflict between the countries that was triggered by air strikes on the Islamic Republic.
Iran had asked that their World Cup matches be switched to Mexico, but FIFA President Gianni Infantino insists that all games be played at the grounds originally scheduled.
The Iranian national team will leave Tehran for a training camp in Turkey on Monday before moving on to their US base at the Kino Sports Complex in Tucson, Arizona, in early June.
Iran are scheduled to get their World Cup campaign underway against New Zealand in Los Angeles on June 15th.