Thousands of oil workers in Nigeria are striking to protest violence and kidnappings in the country's oil-rich Niger Delta region.

Union members stayed away from their workplaces Wednesday, the first day of a called three-day strike. Long lines also formed at filling stations as Nigerians prepared for possible fuel shortages.

Oil workers say loading at several export terminals has been suspended, but industry officials say the strike has not seriously affected production.

The two main unions representing field workers and management want the government to improve safety at oil industry facilities in the Niger Delta. Leaders of the unions say they will meet Thursday to consider new government proposals on security. They may also decide whether to end the strike early.

On Tuesday, gunman killed a Nigerian oil worker when they attacked a boat carrying workers affiliated with U.S. energy giant Chevron.

Niger Delta militant groups say they want local communities to get a greater share of the region's oil wealth. However, many of the recent kidnappings are believed to have been carried out strictly for ransom money.

Nigeria is Africa's largest oil producer. The attacks have reduced output by some 800,000 barrels per day - nearly a third of the country's normal production.

Some information for this report was provided by AFP and Reuters.