A powerful earthquake struck northern Afghanistan at midnight (1 a.m. local time) on Monday, killing at least 20 people, local officials said.

The 6.3-magnitude earthquake injured 320 people, said Sarafat Zaman Amar, a spokesman for the Taliban government's health ministry.

The earthquake hit Mazar-i-Sharif, one of Afghanistan's largest cities. It is home to about 500,000 people.

Rescue and relief efforts are underway. Balkh provincial officials said the death toll could rise. The worst damage was in Solgara district and south of Mazar-i-Sharif, said Haji Zaid, a Taliban spokesman in Balkh province.

"Many people were injured after jumping from tall buildings," Zaid wrote on social media.

A magnitude-6 earthquake in Afghanistan last August killed more than 1,000 people in the east. The damage was more severe in rural areas of the eastern region, where houses are mostly made of wood and mud.