The mob set fire to several lorries Pics: Vivek Jain Riot footage

The east gate of the monument re-opened late on Wednesday before a curfew was imposed in parts of the city.

The violence started after a lorry crushed to death four Muslim men participating in a religious festival.

One man was killed and at least 50 policemen injured in the clashes. Dozens of vehicles were set on fire.

Officials say the situation is now improving quickly, and there has been no violence since the curfew began.

The violence was triggered off by a road accident

The Taj Mahal, a memorial to the wife of Mughal-era ruler Shahjahan, attracts millions of tourists from all over the world.

The men killed in Wednesday morning's accident were all Muslims, who were returning after participating in the festival of Shab-e Barat.

The Uttar Pradesh Principal Home Secretary, JN Chamber, said that officials who allowed trucks to travel on the busy road where the men was killed - in violation of traffic restrictions - will be punished.

Mr Chamber also said an inquiry would be conducted into the incident.

'Berserk'

"A curfew has been imposed in six areas of the city, including in Tajganj [the area around the Taj Mahal]," senior district administration official, Sita Ram Meena, told the BBC.

Angry residents in the Nai Mandi area of the city went "berserk" after the morning accident, the Associated Press news agency quoted state police chief Vikram Singh as saying.

According to reports, mobs set a dozen lorries on fire and clashed with police.

One man was killed and two others were injured when police opened fire on protesters.