At least 15 people have been killed and 78 injured after an earthquake hit western Afghanistan, officials say.

The US Geological Survey said the 6.3 magnitude earthquake struck about 40km from the western city of Herat, close to the border with Iran, at around 11:00 local time (06:30 GMT).

A number of buildings were damaged, trapping people under rubble, Afghan officials said.

At least three powerful tremors followed the initial earthquake.

"We were in our offices and suddenly the building started shaking. Wall plasters started to fall down and the walls got cracks, some walls and parts of the building collapsed." Herat resident Bashir Ahmad told the AFP news agency.

"I am not able to contact my family, network connections are disconnected. I am too worried and scared, it was horrifying," he added.

More than 70 injured people were being treated at the city's main hospital, a health official said.

"The situation was very horrible, I have never experienced such a thing," student Idrees Arsala - the last to safely evacuate his classroom after the quakes began - told AFP.

Herat is located 120km east of the border with Iran and is considered to be the cultural capital of Afghanistan. An estimated 1.9 million people are believed to be living in the province, according to 2019 World Bank data.

The country is frequently hit by earthquakes - especially in the Hindu Kush mountain range as it lies near the junction of the Eurasian and Indian tectonic plates.

In June last year, the province of Paktika was hit by a 5.9 magnitude quake which killed more than 1,000 people and left tens of thousands homeless.