PESHAWAR, Pakistan —  Armed men wounded one police officer at a refugee camp-polling site in Pakistan (search), just hours before the Afghan refugees were to vote in their country's presidential election, police said Saturday.

The attack late Friday was the first serious security scare during preparations for the Afghan election in neighboring Pakistan, where some 740,000 refugees are registered to vote.

Unidentified assailants hurled grenades and fired assault rifles at a camp polling station on the outskirts of Peshawar (search), said Abid Ali Khan, senior superintendent of police.

Police fired back and the attackers fled. One policeman was injured and is in stable condition in hospital, Khan said.

Voting begins across Afghanistan Saturday morning.