Thousands of demonstrators took to the streets of Tehran today, in what’s beginning to look like an exercise in futility — because the mullahs are not going to back down, and they have the power of the Revolutionary Guard and the Basiji militias behind them.

TEHRAN, Iran – Tens of thousands of protesters wearing black and carrying candles filled the streets of Tehran again Thursday, joining opposition leader Mir Hossein Mousavi to mourn demonstrators killed in clashes over Iran’s disputed election.

The massive protest openly defied orders from Iran’s supreme leader, despite a government attempt to placate Mousavi and his supporters by inviting the reformist and two other candidates who ran against hard-line President Mahmoud Ahmadinejad to a meeting with the country’s main electoral authority.

Many in the huge crowd carried black candles and lit them as night fell. Others wore green wristbands and carried flowers in mourning as they filed into Imam Khomenei Square, a large plaza in the heart of the capital named for the founder of the Islamic Revolution, witnesses said. …

The demonstrators had marched silently until they arrived at the square, where some chanted “Death to the dictator!” one of the witnesses said. Press TV showed protesters making V-for-victory gestures and holding pictures of Mousavi and signs that say “Where’s our Vote?”

The witnesses spoke to The Associated Press on condition of anonymity for fear of government retaliation.