Iranian authorities banned five Web sites that comment on current events for "poisoning" public opinion ahead of the crucial mid-March parliamentary elections, the state radio reported on Thursday. The move came two days after Iran's hard-line constitutional watchdog reinstated more than 280 candidates, including 70 reformists, for the polls. Reformists have complained the reversal was insufficient to ensure a fair election. In the past, the authorities have occasionally closed down some of the hundreds of private Web sites that comment on Iranian news and politics. But this was the first time they closed down five at once - a reflection of growing tension ahead of the March vote.