Iran is currently scheduled to play its group matches in the US in this year's tournament.
"We will be preparing for the World Cup. We will boycott the United States but not the the World Cup," Taj said in the video released on Wednesday.
Iran's football federation has opened talks with FIFA about potentially relocating its matches from the United States, though the global governing body has so far maintained that the tournament's schedule remains unchanged.
Mexican President Claudia Sheinbaum said on Tuesday that her country is prepared to host Iran's first-round matches if required, due to the conflict in the Middle East.
Iran's participation at this summer's finals in the United States, Canada and Mexico has been in doubt since the war began last month, with President Donald Trump warning that the safety of Iranian players would be at risk if they travelled to the US.
Asked directly if Mexico was open to hosting the matches, Sheinbaum told a press conference on Tuesday: "Yes."
"Mexico maintains diplomatic relations with every country in the world, therefore we will wait to see what FIFA decides," she added.
FIFA president Gianni Infantino initially said that Trump had given assurances that the Iranian team -- scheduled to face New Zealand and Belgium in Los Angeles, followed by Egypt in Seattle -- would still be welcome.
But the Republican president then triggered uproar last week after stating that Iran's football team should not travel to the tournament "for their own life and safety".
Iran hit back at Trump's comments saying that "no one can exclude Iran's national team from the World Cup".