Iran reopened its border with Iraq to travellers on Tuesday shortly after Iraqi Shi'ite cleric Muqtada al-Sadr called on his supporters to withdraw from the streets, state media reported.
Tehran had closed its borders and halted flights to Iraq amid an eruption of violence in the neighbouring country following Sadr's announcement on Monday that he would quit politics.
Millions of Iranians travel to the Iraqi city of Kerbala every year for the ritual of Arbaeen, which marks the end of a 40-day mourning period for the grandson of the Prophet Mohammad, Imam Hussein. Arbaeen falls on Sept. 16-17 this year.
"As security and calm have been restored in Iraq, all borders are open now," state TV quoted an Iranian official as saying.
Earlier, state TV said Iran had halted all flights to Iraq "until further notice because of the ongoing unrest".
"We are trying to arrange an emergency flight to bring back Iranians from Iraq and Baghdad who are currently at the airport. We hope to evacuate them today," state TV cited a senior aviation authority as saying.