Twin explosions hit oil installations belonging to an Italian oil company in Nigeria's volatile southeastern delta region, officials said Thursday.

Officials suspected sabotage in the explosions Wednesday along two Agip pipelines in Baleysa state.

One of the blasts blew apart an 18-inch oil pipeline at the Clough Creek Tepidapa flow station, and heavy spillage was reported, said Dikivie Ekiogha, an oil industry adviser to the local state governor. A second blast hit a 10-inch riverside pipeline the same day in Lagoagbene.

CountryWatch: Nigeria

There was no word on who was responsible for the attacks.

Militant assaults on oil installations this year in the main oil-producing Niger Delta have cut more than 20 percent of Nigeria's daily oil exports of 2.5 million barrels and helped drive up world oil prices.

Militant groups in the delta say they are fighting for local control of oil revenues by the impoverished inhabitants of the region who feel cheated out of the wealth produced in their backyards.

Nigeria is Africa's leading oil exporter and the fifth-biggest source of U.S. oil imports. Despite vast oil riches, the oil region is mired in crushing poverty.