A car bomb exploded near the home of Afghanistan's acting defense minister in Kabul on Tuesday evening, just hours after the Afghan army urged residents in another city to evacuate ahead of an operation against the Taliban.

The explosion occurred close to Bismillah Mohammadi's residence, where four assailants were also killed by Afghan security, according to Fawad Aman, a defense ministry spokesman. The acting minister was not at home when the attack occurred and his family is fine, Aman added. No one has claimed responsibility for the attack yet.

Earlier on Tuesday, an Afghan army commander had urged people in Lashkar Gah, the capital of Helmand province, to leave their homes if the Taliban was active in their area. Concerns continue to mount over the civilian toll of the militant group's advance on some of the country's biggest cities.