TEHRAN, Iran (AP) — Iran expressed its deep displeasure Friday over a Taliban delegate's failure to stand during the Iranian national anthem at an event in Tehran, state-run media said, following a similar incident in Pakistan earlier in the week.

The incident involving the Taliban delegate to the Islamic Unity Conference in the Iranian capital Thursday followed an episode in Pakistan in which a Taliban diplomat did not stand for the Pakistani anthem on Wednesday. Both host countries considered the gestures disrespectful, and in both cases Taliban officials have said it is customary in their country to sit when music is played.

Iran's Foreign Ministry summoned the caretaker of the Afghan Embassy in Tehran on Friday to condemn the act by the Taliban delegate, Azizorahman Mansour, Iran's state-run IRNA news agency reported. The ministry called it an “unconventional and unacceptable action by the Afghan envoy.”

The Islamic Unity Conference is an annual event held in Iran to promote unity and solidarity among various Islamic sects, particularly between Sunni and Shia Muslims.

The Taghrib News Agency, which reports on Islamic world news, published a video from Mansour apologizing for his behavior at the conference, but saying it was in accordance with the norms in Afghanistan.

“In our country when we sing songs, we sit. I followed that norm," Mansour said. “We apologize to the people who were upset.”

IRNA quoted the Afghan Embassy chief as saying the action by Mansour was a personal act and did not reflect the views of the Taliban government. Following the incident Wednesday in Pakistan, the Taliban had released a statement saying the diplomat did not stood up there because music was part of the anthem.

Iran and Afghanistan have a 960-kilometer (570-mile) long border, and it became has become a lifeline for many Afghans who have flocked to the neighboring country to search for work. Iranian authorities say about six million Afghans are in Iran. Activists believe the number is much higher.

Iran doesn’t formally recognize the Taliban government in Afghanistan, and has called for the formation of an inclusive Afghan government that involves all ethnic and religious groups. However, Iran maintains political and economic ties with Kabul and has allowed the Taliban to manage the Afghan embassy in Tehran.