Iran has greeted Saudi Arabia on the kingdom's National Day amid a rapprochement between the two regional rivals.
In separate letters to Saudi King Salman bin Abdulaziz and Crown Prince Mohammad bin Salman, Iranian President Ebrahim Raisi extended his felicitations to the Arab country, his office said.
The Iranian Embassy in the Saudi capital, Riyadh, published the two letters on social media.
In a separate statement, the Iranian Foreign Ministry also extended its "sincere congratulations and blessings to the leadership and people" of the Kingdom of Saudi Arabia.
"Strengthening and consolidating relations between the two countries within the framework of the neighborhood policy and regional cooperation provides valuable and promising opportunities to achieve greater prosperity for all countries of the region," the statement said.
Celebrated on Sept. 23 every year, the Saudi National Day marks the unification and renaming of the Kingdom of Najd and the Hejaz under a new name: the Kingdom of Saudi Arabia in 1932.
Iran and Saudi Arabia restored their diplomatic ties in March this year after seven years following marathon fence-mending negotiations hosted by Iraq, Oman and China.
The two neighbors severed diplomatic ties in January 2016 after the Saudi Embassy in Tehran and consulate in Mashhad were attacked by mobs following the execution of a Saudi Shia cleric.
Saudi Arabia's new ambassador to Tehran Abdullah bin Saud Al-Anzi submitted his credentials to Iranian Foreign Minister Hossein Amir-Abdollahian earlier this month and formally assumed the charge.
A week before that, Iran's new ambassador to Saudi Arabia Alireza Enayati also submitted his credentials to the director general of the Saudi Foreign Ministry, Abdul Majid al-Sameri.
Saudi King Salman has invited Raisi to visit Riyadh and Iran has also extended an invitation to the monarch to visit Tehran.
Last week, top football clubs of the two countries, Al-Nassr and Persepolis, played a match in the AFC Champions League at Tehran's Azadi Stadium after many years.
