A Nigerian firm backed by Britain's Afren and a mainly local consortium have bought major stakes in onshore oil blocks from Shell, Total and Agip for more than $700 million, officials announced Thursday. The deals for 45-percent stakes in two leases were long in the making and come with Shell, historically the largest producer in Nigeria, seeking to sell off its share in a number of onshore blocks viewed as marginal. Analysts have said Shell, previously the operator for both blocks, has seemed willing to shift more of its focus offshore in Africa's largest oil producer, where the risks of sabotage and militant attacks are lower. Shell said in a statement announcing the sales that it "has been in Nigeria for more than 50 years and remains committed to keeping a long-term presence there -- both onshore and offshore." In one deal, First Hydrocarbon Nigeria Limited, backed by Afren, announced it paid $147.5 million for a 45-percent stake belonging to Shell as well as Nigerian divisions of France's Total and Italy's Agip. The block currently produces some 6,000 barrels per day, but the company plans to boost that to 40,000 bpd in four years and eventually 50,000. "FHN has today announced the completion of its acquisition of a 45 percent interest in (oil mining lease) 26 from SPDC, Total and Agip," a statement said. SPDC is Shell's local joint venture, the Shell Petroleum Development Company of Nigeria. The remaining 55 percent is owned by Nigeria's state oil firm, the Nigerian National Petroleum Corporation. FHN will partner with the state firm's exploration and production arm. Afren holds a 45 percent stake in FHN, which it established with the support of Nigerian banks First City Monument and Guaranty Trust. In the second deal for oil mining lease 42, the Neconde Energy Limited consortium purchased the 45-percent stake previously belonging to the three oil majors. The state firm also holds the remaining 55 percent in that block. The consortium is majority Nigerian-owned and includes Nestoil Group, Aries E&P Company Limited and VP Global, as well as Polish firm Kulczyk Oil Ventures. Neconde paid $585 million for the stake in the block which includes several fields, according to Kulczyk. "Operations had been shut down because of militant activity, but production from the Batan field resumed earlier this year and is currently producing circa 15,000 barrels of oil per day," Shell said. Shell held 30 percent in each of the blocks, while Total owned 10 percent and Agip held five percent. Pipelines in the oil-producing Niger Delta region are regularly damaged by oil thieves seeking crude to sell on the black market, while militants claiming to be fighting on behalf of impoverished communities have carried out scores of attacks on facilities. Militant-related violence has sharply declined since a 2009 amnesty deal, but oil theft is believed to be on the rise. Nigeria has been pushing for more local involvement in the country's petroleum industry. The country currently produces more than two million barrels per day.