"The consequences risk becoming very serious and could affect the people living in Rinkeby," he told the TT news agency.
Education Minister Jan Björklund and Integration Minister Nyamko Sabuni on Wednesday visited Rinkeby to take stock of the situation.
Up to 100 youths have rioted for two straight nights in the Stockholm suburb, throwing bricks, setting fires and attacking the local police station, police said Wednesday.
"They set fire to a school building ... They tried to set fire to the police station and other buildings and vehicles, but mostly they have thrown rocks and bricks at police and fire fighters," police spokesperson Mats Eriksson told AFP.
He said no one had so far been injured in the riots which began on Monday in the northern suburb long blighted by high levels of unemployment and home to a large number of first and second generation immigrants.
"The whole thing started when a group of young adults were not permitted to enter a junior high school dance. They got angry and started throwing rocks through the school windows," Eriksson said.
Up to 100 people went on a rampage, breaking 23 windows at the local police station and setting at least one car ablaze and leaving a school set up as a mentor programme for young people to find their way into the labour market, burned to the ground.
Three people were arrested late Monday, but had since been released, Eriksson said, adding that "I would say things got worse" Tuesday night, when the school and four or five cars were set on fire.
"Fire fighters were there but they couldn't approach the blaze (at the school building, which was basically burned to the ground), because they were under attack," he said.
Eriksson said local police in the western part of Stockholm would receive reinforcements from across the capital to try to calm tensions in Rinkeby.
"This is an extremely serious situation and we must bring it to an end as soon as possible, otherwise it will keep getting worse," he said mirroring Reinfeldt's words, adding the riots were "an attack on both the society as a whole and on the residents in the area."