KABUL — More than a dozen Afghan civilians were killed and many others wounded Thursday when clashes broke out on the border between Afghanistan and Pakistan, Afghan officials said.

Ahmad Bahir Ahmadi, a spokesman for the governor of Kandahar province, which borders Pakistan, said 15 people were killed and 80 wounded. One Afghan official, who spoke on the condition of anonymity because he was not authorized to speak to the media, said more than a dozen Afghan civilians were killed.

The Afghan Defense Ministry said at least nine people, including a child, were killed and blamed Pakistani forces for the attack. In a statement, the ministry warned that the Afghan Air Force and special forces units are on high alert and prepared to reciprocate if violence continues.

The Pakistani Foreign Ministry appeared to reject that assertion, saying in a statement Friday that “Afghan forces opened unprovoked fire on innocent civilians gathered towards Pakistan’s side of the international border."

“Pakistan troops responded to protect our local population and acted only in self-defense,” the statement said, claiming Afghan forces opened fire first and casualties also occurred on the Pakistani side of the border.

Abdul Malik Achakzai, a doctor in charge of the Chaman Civil Hospital in Pakistan, told Pakistani media outlet Dawn that three dead bodies and nearly 20 wounded people were brought to his hospital after the clashes.

Movement between Afghanistan and Pakistan has been restricted recently because of the novel coronavirus pandemic, but some restrictions were relaxed to allow people to cross for Eid al-Adha, a Muslim holiday being celebrated this week. Crowds of people gathered on both sides in hopes of crossing, Reuters reported.

The Pakistani Foreign Ministry said that officials had relaxed some border restrictions to allow traders and people hoping to enter the country for the holiday to cross. Those people were then “deliberately targeted by Afghan forces for incomprehensible reasons,” the ministry said.

But Mohammad Aref Noorzai, an Afghan lawmaker from Kandahar province, said the clashes began when Pakistani forces opened fire at Afghan protesters on the border.

“A peaceful protest was taking place at the border, then Pakistani forces opened fire at them,” he said. “The first bullet was fired by Pakistanis.”

Noorzai said Afghan police reciprocated, firing at Pakistan forces’ positions when they saw Afghan civilians were harmed. “Pakistanis targeted civilians and Afghan forces alike,” he said.

The protesters were mainly merchants carrying fresh fruits and vegetables to export to Pakistan, he said, adding that tensions were rising in part because traders feared long wait times would spoil their goods.

Relations have been tense between the two countries for years, with Afghan officials accusing Pakistan of harboring militants who carry out attacks in Afghanistan, and Pakistan claiming Afghanistan backs militants opposed to the government in Islamabad.

O’Grady reported from Washington. Susannah George in Kabul and Haq Nawaz Khan and Shaiq Hussain in Islamabad contributed to this report.