Nigeria's oil output has risen to between 1.6 million and 1.7 million barrels per day after the government beefed up security to curb crude theft, Chief of Naval Staff Emmanuel Ikechukwu Ogalla said on Tuesday.

Crude production in Nigeria, a member of the Organization of the Petroleum Exporting Countries (OPEC), stood at 1.2 million barrels per day in February, Ogalla said. Oil major Shell has exited the country.

"We have stepped up surveillance and enforcement in the oil producing areas," the naval chief said.

"Right now, as we speak, the Nigerian Navy has 12 vessels on the sea to protect oil production and stem oil theft. We have arrested over 16 vessels, so far."

Ogalla said the force has blocked channels for the sale of illegally refined petroleum products.

The country's oil minister Heineken Lokpobiri said in May that Nigeria could produce 6 million barrels of oil per day with adequate investment in its energy sector.

He added that Nigeria and other African oil-producing countries lack the capital to explore and produce their oil and gas.

Reuters