Firefighters tackle a blaze

The 56-year-old suffered third degree burns to 20% of her body in the attack.

Witnesses said a youth poured petrol over the woman and then threw a Molotov cocktail on to the bus she was travelling on in the suburb of Sevran.

Other passengers were able to flee but she was unable to escape because of her disabilities.

It was the worst incident so far in more than a week of rioting.

For the first time, there were also signs of copycat rampages elsewhere in France.

Police said several cars in the eastern city of Dijon were set alight, while similar attacks took place in the western Seine-Maritime region and the Bouches-du-Rhone in the south of the country.

More than 160 cars were reportedly torched in the Paris region, as well as 33 in the provinces.

But police said the night seemed calmer than the one before, when 315 vehicles were burnt in the Ile-de-France region around the capital.

Buses, fire engines and police were again stoned in the Paris suburbs, with five policemen reported slightly injured.

However, there were fewer direct confrontations between police and "troublemakers".

One of the worst incidents took place at Neuilly-sur-Marne where police vans came under fire from pellet pistols, but nobody was hurt.

Neuilly-sur-Marne is in the worst-hit northeastern region of Seine-Saint-Denis, where 1,300 officers were deployed, and more than 30 people were arrested there and elsewhere.

The rioting is a direct challenge to the authority of the French government and to Prime Minister Dominique de Villepin in particular.

On Thursday he told parliament authorities "will not give in" to the violence and will make restoring order their "absolute top priority".