Iranians are defying religious hard-liners to celebrate the "Festival of Fire," a nearly 4,000-year-old Persian tradition.

In Tehran, people lit bonfires in public places, set off fireworks and sent wish lanterns floating into the night sky as part of an annual ritual that dates back to at least 1700 B.C. and is linked to Zoroastrianism.

Since the 1979 Islamic Revolution, hard-liners have discouraged the celebration, viewing it as a pagan holdover from pre-Islamic times. Police warned revelers to avoid major streets and squares but have not moved to disperse them.

The holiday comes ahead of Nowruz, the Persian new year, which will be celebrated on March 21.