A senior Afghan police official regarded as one of the country's most powerful men has banned the use of the Pakistani currency in the key southern province of Kandahar.

Kandahar police chief, Gen. Abdul Raziq, said on Sunday that using the Pakistani rupee is now a crime. But he says he hasn't yet decided on the punishment.

The rupee has been widely used in Afghanistan's eastern and southern provinces bordering Pakistan.

Raziq's ban came into effect last week. Traders say it has had an impact, with the afghani strengthening in recent days.

Raziq says he is retaliating against Pakistan's protection of the Taliban, a charge that Pakistani authorities have denied.

Taliban leaders moved across the border when the U.S. invaded in 2001 and are believed to live under Pakistan's protection.