Lagos, Nigeria ? Nigerians ignored scattered violence and tropical downpours to vote Saturday in legislative elections that are a crucial test for civilian rule in Africa’s most populous nation.

The balloting for 469 seats in the House of Representatives and Senate is the first since 1999, when the former military regime administered the polling.

Military coups have scuttled Nigeria’s previous attempts to hold democratic, civilian-run elections.

Some violence and voter intimidation were reported Saturday, including claims by Ijaw militants that they effectively blocked voting in dozens of villages in the oil-rich Niger Delta to protest electoral boundaries.

In southeastern Nigeria, witnesses said four people including two policemen were killed in an armed ambush on opposition politician Fidel Ayogu in the city of Enugu.

Despite the problems, election commission chief Abel Guobadia said early returns indicated a high turnout across the country of 126 million people, although figures were unavailable. Sixty-one million voters were registered for Saturday’s ballot, which features 3,000 candidates.

The vote precedes presidential elections April 19 that will pit President Olusegun Obasanjo — a former military ruler turned civilian leader — against 19 opposition candidates, including three former army generals.

The voting was extended to today in some troubled areas, election officials said.

But Ijaw militant leader Dan Ekpebide warned late Saturday “it will be bloody” if officials tried to extend voting in their areas.

Ethnic Ijaws had pledged to prevent the elections in Ijaw-dominated parts of the swampy Niger Delta, where most of Nigeria’s oil is drilled. The militants are angry authorities refused to change electoral boundaries, which they say favor rival Itsekiris.

Last month, fighting between ethnic militants and government troops left more than 100 people dead and shut down 40 percent of the country’s oil production. Nigeria is the fifth largest supplier of U.S. oil imports.

More than 10,000 people in Nigeria have been killed in political, ethnic and religious violence since Obasanjo was first elected in 1999, ending 15 years of brutal military rule.

“If the problems seen today are not addressed … they could impact very negatively on the presidential elections,” warned Festus Okoye, head of the private Transitional Monitoring Group, which provided 10,000 observers.

Okoye said in some cases, voters faced intimidation at the polls and were forced to cast their votes in full view of bystanders.

Obasanjo denied allegations of intimidation.