Iran's Supreme Leader Ayatollah Ali Khomeini welcomed the Iranian New Year as one of "production, support and removal of barriers" in a live televised speech on Saturday.
"There is good ground for a production leap," Khomeini said, adding the government needed to get rid of any legal obstacles to higher output and growth as the economy suffers under U.S. sanctions.
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The army fired gun salutes at Tehran's Azadi Square to usher in Nowruz - New Day in Persian and the most important date in the Iranian calendar, marked at the spring equinox - and the beginning of the year 1,400, which is celebrated in a dozen countries stretching from the Caucasus to central Asia.
In Washington, U.S. President Joe Biden issued a Nowruz message calling for peace, prosperity and understanding.
"That is the message and the joy of Nowruz that we are honouring ... This year, perhaps more than ever, that message is badly needed," Biden said in a White House statement.
Biden's administration is exploring ways to restore the 2015 nuclear deal that Iran signed with major world powers, but which was abandoned in 2018 by President Donald Trump who reimposed sanctions.
The United States and the other Western powers which originally signed up to the 2015 deal appear to be at an impasse over which side should return to the accord first, making it unlikely U.S. sanctions that have crippled its economy can be quickly removed.
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In a separate message, President Hassan Rohani said he was hopeful the new year will see the end of the sanctions.
"We will defeat the sanctions ... I am more hopeful than eight years ago" Rohani said, referring to when he was elected for his first term.
Rohani is barred from standing for a third term and the slate of presidential candidates has yet to be finalised.
Iran's hardliners say the U.S. sanctions are proof Rohani's policy of reaching out to the country's enemies was a failure. A delay in progress on returning to the nuclear deal could hurt the chances of a moderate succeeding Rohani, although the final decision on any diplomatic initiative would be taken by Khomeini rather than the elected president.
Khomeini said on Saturday that the June election will likely bring to office "new managers who most probably will be energetic and strongly motivated."