This was the second attempt in a month by protesters to burn the Iranian consulate in Najaf. In the first attempt, Molotov cocktails were thrown over the consulate walls but the flames were put out and the damage was limited.

The demonstrators in Najaf are almost all Shiites, and Shiite religious authorities there have encouraged the protests, although they have insisted that they remain peaceful.

The Grand Ayatollah Ali al-Sistani, the most senior Shiite cleric in Iraq, has faced intense pressure to resolve the standoff between the protesters and the government.

Although he usually tries to stay out of direct involvement in Iraqi politics, he has urged restraint by the government and admonished the protesters to refrain from violence. However, he has used increasingly strong language urging the government to make far-reaching changes in its election law, to crack down on corruption and to accommodate the demands of the “peaceful protesters.”

The majority of the demonstrations have been peaceful, but in Baghdad, the capital, and in the south, the security forces have shot unarmed demonstrators, killing more than 320 and wounding as many as 15,000 since the protests began, according to the United Nations office in Iraq.

In a number of places, protesters have set fire to the headquarters of political parties, damaged government buildings and engaged in revenge killings.

Several analysts predicted that Iran would pressure the Iraqi government to have a tough response to the Najaf attack.