ISLAMABAD — Afghanistan and Iran have launched a joint investigation into allegations that dozens of Afghan migrants who crossed illegally into Iran were tortured by Iranian border guards and thrown into a river, where at least 16 drowned.

Afghanistan’s foreign ministry announced the launch of the joint investigation Wednesday after reports of the torture and killings emerged this week. The announcement follows criticism from Afghan and U.S. officials. The Afghan presidential spokesman called the reported killings “unforgivable crimes.”

The allegations come as coronavirus lockdowns in Afghanistan have caused unemployment to spike and food prices to soar. As coronavirus spread in Iran earlier this year, more than 200,000 Afghans returned to Afghanistan. And now as the Afghan economy has been crippled by the pandemic, some are trying to return to Iran in search of work.

Afghanistan’s acting foreign minister, Mohammad Hanif Atmar, told lawmakers Wednesday that talks with Iranian officials “ended with tension,” according to Afghan media reports. Atmar said that 16 bodies had been recovered from the site and that 18 to 20 people are missing.

Atmar launched a separate investigation by the Afghan government into the incident earlier this week, pledging in a tweet Tuesday, “we will pursue this unforgivable crime with all our country’s diplomatic means until we achieve justice and righteousness.” Atmar’s post included images from Afghan social media of bodies wrapped in cloth loaded into the back of a vehicle.

The U.S. Embassy in Kabul voiced support for the move and called on Iran “to cooperate fully and hold the guilty accountable.”

Many Afghan laborers informally cross the nearly 600-mile-long border with Iran in search of work. As undocumented workers, they endure harsh conditions with little legal protection. An estimated 2.2 million Afghans were living in Iran before the coronavirus pandemic, according to Afghan officials.

Sayed Abdul Basit Ansari, the spokesman for Afghanistan’s Ministry of Refugees and Repatriation, said Afghans returned from Iran during the coronavirus outbreak because Iranian hospitals refused to treat them. He said it was too early to comment on the ongoing investigation into abuse by Iranian border guards.

More than half of Afghanistan’s population lives below the poverty line, and coronavirus lockdowns have caused unemployment to soar. Food prices have also spiked as restrictions on travel have interrupted supply lines. Save the Children is warning in a report this month that rising food prices are putting a third of the population, including more than 7 million children, at risk of hunger.

As of Wednesday, Afghanistan had identified more than 3,300 confirmed coronavirus cases and 104 deaths, according to the health ministry. Testing remains limited, and a United Nations body has warned that Afghanistan may have one of the highest coronavirus infection rates in the world.

Sharif Hassan in Kabul contributed to this report.