Zarif’s remarks followed his phone talks with his Afghan counterpart Mohammad Hanif Atmar on Sunday night after a number of Afghan media outlets alleged on May 1 that more than 40 illegal migrants had been arrested by Iranian border guards and thrown into Harirud River.
"Our friends believe that the incident took place on Afghan soil, but because of the importance of Afghanistan for the Islamic Republic and the brotherly relations we have with Afghanistan, a joint committee is to carry out it [investigation] in both countries," IRNA quoted Zarif as saying.
He added that the formation of the committee has been proposed by the Afghan foreign minister.
Afghanistan’s Foreign Ministry said on Sunday Zarif and Atmar agreed to hold inquiry into the incident which happened to the Afghan migrants who tried to illegally cross the countries' common border.
During the talks, Zarif assured his Afghan counterpart that an Iranian investigative team would soon begin looking into the matter, while Atmar notified the Iranian minister that an Afghan delegation had already visited the northwestern Afghan province of Herat, where the river partly flows, and begun a probe.
The ministers agreed that joint investigative bodies could meet in Herat and the northwestern Iranian city of Mashhad to share their findings.
The Afghan Foreign Ministry said the investigations would seek to verify credibility of the media reports, and prevent any future incidents.
On May 3, Iran’s Foreign Ministry spokesman Seyyed Abbas Mousavi said the incident occurred on Afghanistan’s territory, citing police border guard findings.
His remarks came hours after Iranian police border guard in a statement strongly denied the allegations about arrest of illegal Afghan migrants by its forces on the countries’ common border, stressing that the incident occurred on Afghanistan’s soil.
Afghanistan shares more than 750 kilometers of border with Iran. About three million Afghans – a mix of refugees and illegal migrants – live in Iran, a large number of them having arrived after their country plunged into conflict in the 1980s.
Young Afghans constantly flow across the border to seek work, many of them smuggled through dangerous deserts, often traveling for a week at a time packed into the back of pick-up trucks.
Press TV contributed to this story.