Burmese opposition groups say police broke up a demonstration and detained several protesters after they defied police warnings and took to the streets demanding an end to electricity blackouts.

A spokesperson for the National League for Democracy said police dispersed the protest of at least 100 people Thursday in the town of Pyay, about 260 kilometers northwest of Rangoon.

Witnesses and party officials accused police of handling the protesters roughly, saying some were injured. At least three demonstrators were detained for questioning. They were released hours later.

The rallies started Sunday in the city of Mandalay, before also spreading to the commercial capital of Rangoon. Until Thursday, police had allowed the protests to go ahead, despite warning demonstrators not to participate.

They are the largest protests in years in the Southeast Asian nation, which — until last year — had endured a half-century of harsh military rule.

The protesters are calling for 24-hour electricity, and complain of frequent blackouts that often last for six hours or longer in major cities.

A Wednesday report in the state-controlled New Light of Myanmar said the government has purchased dozens of new generators to deal with the electricity shortage.

The last major protests in Burma were in 2007, when Buddhist monks and others launched a massive campaign of disobedience against military rule.

Those protests, known as the Saffron Revolution because of heavy monk participation, were crushed with overwhelming military force. At least 1,000 people were detained during the crackdown, with hundreds of unarmed protesters injured.