Updated

MAPUTO, Mozambique (AP) — Mozambicans found Monday they could not send text messages, after others used the technology to call for protests in this impoverished country over increases in food, water and electricity prices.

Protests last week in the capital, Maputo, turned violent, with at least 10 people killed in clashes with police. Maputo was calm over the weekend and early Monday, though many workers and students stayed home for fear of more violence. Police reported finding a few burning tires blocking streets, but no protesters at the barricades.

Maputo police spokeswoman Silvia Mahumane said Monday that police were patrolling the capital and that the city was calm.

She said police did not use excessive force — as some protesters say they did — in handling the protests.

"I think the rioters used force against the police," she said. "What our men did was to restore law and order."

It was not immediately clear whether the interruption in cell phone messaging was part of a government crackdown.

Also Monday, state radio reported nine people have been arrested, accused of incitement for sending cell phone messages calling for protests. The radio report said six were arrested Sunday and another three on Monday in Nampula for trying to spread the protests to that northern province. Nampula has so far seen no unrest.

No one has claimed responsibility for organizing the protests sparked by rises in the government-set price of bread, water and electricity.

Energy Minister Salvador Namburete told state radio on Monday that the recent increase in the price of electricity was necessary to cover the cost of electrifying rural areas and constructing a new power line in the country's northwest.

He added that the rioters caused more than $400,000 worth of damage to electric infrastructure.

Antonio Fernando, the minister of trade and industry, told the Associated Press on Monday that the government is already indirectly subsidizing bread, through scrapping import duties and a tax on wheat and flour.

Authorities have said they were trying to trace who sent the first unsigned cell phone messages calling for protests in the southern African nation. Over the weekend, text messages calling for calm and portraying protests as unpatriotic began to appear — they, too, were unsigned.

Protesters on the streets have said even they do not know who is orchestrating the demonstrations, and that they believe those behind them want to remain anonymous for fear of arrest.

In an AP interview over the weekend, Afonso Dhlakama, leader of the main opposition Renamo party, said his party was not responsible for the protests. But he and other opposition leaders have tried to gain political mileage from them.

Dhlakama accused the police of using excessive force, and said the rioters' demands were understandable. He noted that many of those who took to the streets were young.

"The children feel the pain of their fathers, who cannot afford to pay fees for schooling," he said.

Daviz Simango, another opposition leader, also has called on the government to meet protesters' demands. A third opposition figure, Jose Manuel Campira, on Monday called for more demonstrations — but said they should be peaceful.

The government has said it will remain firm on the higher prices. It has said keeping food prices low is difficult because so much of the country's food has to be imported. Mozambique grows only 30 percent of the wheat it needs.