ASSOCIATED PRESS WRITER

FRANK AIGBOGUN

LAGOS, Nigeria (AP)—Thousands of people ignited bonfires, hijacked cars and rampaged through the streets of Nigeria’s biggest city today to protest the military dictator’s cancellation of last month’s presidential elections.

The street violence broke out just hours before major human rights groups had planned a march to protest the government’s decision to annul the June 12 vote, which was to return this nation of 88 million people to civilian rule.

Authorities sealed off the central business district of this sprawling city of 1.3 million residents as more than 20 areas exploded into violence. Running mobs lighted giant fires, stole cars and snarled traffic in what already was one of the world’s most congested cities.

Crowds of residents tried to get out of the way of mobs and cars drove the wrong way on the city’s dangerous roads.

It was the first serious unrest to hit Lagos since the dictatorship on June 16 abruptly voided the results of the balloting, which according to unofficial counts was swept by business tycoon Moshood K.O. Abiola.

Military ruler Gen. Ibrahim Babangida claimed the voting that he carefully organized was rigged and declared a new ballot must be held July 31. Babangida handpicked the only two candidates allowed to run in the June 12 vote and has repeatedly reneged on promises to return Nigeria to democracy.

‘‘Abiola must be president! Babangida must go!’‘ rioters shouted.

The government released the details of the new election Sunday, but few politicians planned to participate in them. Abiola’s Social Democrats said they will boycott the ballot.

Parliament also said it will have nothing to do with the new election and at least 30 high-ranking army officers resigned to protest the election cancellation.

Even a member of Babangida’s latest electoral commission submitted her resignation today.

‘‘I don’t know whom I’m supposed to be serving on this commission,’‘ said Tosin Kalai. ‘‘Certainly not the Nigerian people who massively expressed their will on June 12.’‘

Babangida’s government has been increasing its crackdowns on the press and on human rights groups in recent weeks. Scores of activists were detained on Friday, including Nigeria’s most prominent rights leader, Beko Ransome-Kuti, who was freed Saturday.

Babangida’s heavy-handed moves have had the effect of bringing together disparate groups in this tense nation often torn by religious and ethnic differences.

Christian and Muslim leaders were planning to meet this week to discuss how they can intervene jointly in the political crisis.

This oil-rich nation has been plunged into economic chaos by corruption and mismanagement. Unprecedented poverty has added to Babangida’s unpopularity in a country where fuel, power, water and housing shortages are pervasive.