Hundreds of thousands of people turned out in Iran, Iraq and Lebanon to honor the Shi'ite holy day of Ashura, and to mark the seventh century slaying of Imam Hussein, grandson of Islam's Prophet Muhammad.
In the Iranian capital Tehran, government-led mourners paraded down main avenues, beating drums and crying out religious slogans in unison.
Eyewitnesses described a heavy police presence along major thoroughfares, as helicopters hovered over the crowds to monitor the situation. Hundreds of anti-government demonstrators were arrested last year for shouting slogans against the Iranian government during Ashura.
One opposition student group spoke of skirmishes between some Ashura participants and security forces in parts of Tehran. Unconfirmed reports also say several people were arrested for shouting slogans against President Mahmoud Ahmadinejad.
Official state media showed pro-government religious clerics leading ceremonies in the holy city of Qom, while apparently ignoring others who have been more critical of the government.
State TV showed crowds of mostly young Ashura celebrants in dozens of cities. The fervor of the ceremonies was visible on the faces of hundreds of young men in the city of Yazd, dressed in black and beating themselves on the chest to mark the death of Hussein at Karbala in 670 AD.
Many had tears in their eyes as they beat themselves, crying out, "Oh Hussein, Oh Hussein." The TV also showed periodic broadcasts from Karbala, in neighboring Iraq.
In Iraq, local TV showed men thrashing themselves with chains, some on their heads to draw blood. Spilling blood is part of the ritual to commemorate the bloody end of Hussein and his outnumbered followers at the hands of the Caliph Yazid.
Iraqi government TV noted that several-million visitors from across the Arab world had turned up in Karbala and Najaf for the annual event. Men on horseback, dressed in costumes of the period also appeared in the city of Kazemia to depict the epic and fatal end of Hussein.
In neighboring Turkey, former Iranian Foreign Minister Ali Akbar Velayati addressed a crowd of Ashura mourners, alongside Turkish Prime Minister Recip Tayyib Erdogan. Both men urged Sunni and Shi'ite Muslims to end their conflicts and unite.
In Lebanon, tens of thousands of Shi'ite mourners turned out in Beirut's southern suburbs to listen to Hezbollah leader Sheikh Hassan Nasrallah address them by video-link. Nasrallah has not appeared in public for several years.
Nasrallah spoke in harsh tones and admonished his enemies. He claimed that Hezbollah has defeated Israel repeatedly and will do so, again. He also complained about what he calls a psychological war against his group, demanding that his followers close ranks to defeat what he calls outside plots and threats.
Hezbollah's al-Manar TV showed groups of young men and groups of young women mourners, chanting and walking slowly in long processions. It noted that groups of male and female mourners celebrated separately.