At least three people were killed and more than a dozen injured after Taliban militants opened fire during protests against the group in the Afghan city of Jalalabad on Wednesday, two witnesses told Reuters.

The witnesses said the deaths followed an attempt by local residents to install Afghanistan's national flag at a square in the city, some 150 km (90 miles) to the east of Kabul.

Video footage shot by Pajhwok Afghan News, a local news agency, showed protesters in the city who were carrying the Afghan flag fleeing with the sound of gunshots in the background.

A former police official told Reuters separately that four people had been killed and 13 injured in the protests, without elaborating further.

It was not possible to verify how the deaths occurred.

"There were some troublemakers who wanted to create issues for us," a Taliban militant present in Jalalabad at the time of the incident told Reuters. "These people are exploiting our relaxed policies."

Taliban spokesmen could not immediately be reached for comment.