Iran said today more than 4,000 people had been arrested during protests against Islamic clerical rule earlier this month.
Analysts said the new number from Iran's Prosecutor General Ayatollah Abdonnabi Namazi suggested the protests had been larger than authorities had previously acknowledged, as it was a much higher figure than originally thought.
The demonstrations started in Tehran about three weeks ago. Hundreds of university students were joined by a several thousand ordinary people each night who chanted slogans against Iran's clerical rulers and called for greater democracy and freedom.
The protests, which included harsh criticism of moderate President Mohammad Khatami as well as the conservative clerics who have blocked his attempts at reform, spread to more than half a dozen other cities.
But they were soon stamped out by a large security response involving riot police and hardline vigilantes armed with batons and chains who are fiercely loyal to conservative clerics.
Officials say they will prevent students holding any events to commemorate the 1999 attack that sparked the worst street unrest seen in Iran since the 1979 Islamic revolution.
Reformist legislators this week criticised Mr Khatami for not taking a firmer stand against the wave of recent arrests. Many families have not been informed where their arrested relatives are being held.