Ruhollah Latifi, spokesman of Iran's Customs Organization, said Thursday evening that transport of goods between Iran and Afghanistan had been curtailed following the Taliban capture of two key Afghan border crossings earlier in the day. This came as United President Joe Biden delivered a speech announcing the two-decade US military operation in Afghanistan would end August 31.

The development cast a shadow on two-day talks between the Taliban and the Afghan government in Tehran that concluded Thursday with a joint commitment to peaceful resolution of the Afghan conflict. The Taliban's new gains were only hours after the two sides issued a statement describing the talks as "cordial."

Latifi named the two border crossings as Dogharoon-Islam Qala, near the city of Taybad in Iran's Khorasan Razavi province, and Mahiroud-Sheikh Abu Nasr Farahi, near the city of Birjand in South Khorasan province. Latifi called on Iranian businesses to halt transports to the two crossings until further notice but said the Milak-Zaranj crossing in Sistan-Baluchestan province was still open.

The border crossings in Dogharoon, designated a special economic zone by Iran, and Mahirood are crucial to Iran's trade with landlocked Afghanistan.  Iran exports construction material, raw materials and food to its eastern neighbor. In 2019 Iran's exports to Afghanistan amounted to $1.24 billion, 14.5 percent of Afghanistan's imports, while Afghanistan's exports to Iran amounted to just $15 million, 1.72% of Afghan exports.

The Taliban have recently made considerable territorial gains in fresh offensives, particularly in the north, the traditional stronghold of many former mujahedeen leaders. Kabul has in response tried to arm local volunteers and militias.

Biden’s announcement Thursday that the US Afghan military operation would end August 31, was made in a speech from the White House’s East Room. “We did not go to Afghanistan to nation build,” he said. “Afghan leaders have to come together and drive toward a future.”

Iran's Arabic-language channel, Al-Alam, reported Thursday that Afghan border guards fled to Iran when the Taliban captured the two Afghan border posts. Videos posted on Twitter Thursday showed Afghan soldiers fleeing to the Iranian side of the border and the Taliban taking down the flag of the Afghan government. Shahabuddin Delawar, head of a Taliban delegation visiting Russia, said Friday that the Taliban now controlled 85 percent of the country, but assured "neighbors and the world" that they posed no threat.

Babak Taghvaee, defense analyst, has in Twitter posts recently reported Iran already deploying troops and equipment along its eastern borders following Taliban gains and the defection of Afghan soldiers to Iran. On June 29 Taghvaee shared a video of Iran's Revolutionary Guards (IRGC) Aerospace Force that he said showed movement of drone-control stations from Tehran toward Birjand.

Another video posted by Taghvaee on June 24, which he said had been recorded by civilians in north-east Iran, shows deployment by the IRGC of tens of BMP-1 and BMP-2 infantry fighting vehicles near the Afghan border.