ABUJA (Reuters) -Nigeria has approved the sale of Exxon Mobil Corp's onshore assets to Seplat Energy, the chief executive officer of the country's upstream regulator said on Monday, more than two years after the $1.28 billion deal was first agreed.

The sale had been under scrutiny as it awaited regulatory approval since it was first announced in February 2022.

President Bola Tinubu said on Oct. 1 the deal would receive ministerial approval in a matter of days after getting clearance from the regulator.

Nigerian Upstream Petroleum Regulatory Commission (NUPRC) CEO Gbenga Komolafe said on Monday at an event in the capital Abuja that the ministerial approval had been granted.

Under the deal, Seplat will own 40% of four oil mining leases and associated infrastructure, including the Qua Iboe export terminal, and 51% of Bonny River natural gas liquids recovery plant previously owned by Mobil Producing Nigeria Unlimited, Exxon's local unit.

Oil majors operating in Nigeria - Africa's largest oil exporter - have been retreating from onshore operations hampered by theft and sabotage, opting to focus future investments on newer and more lucrative deep offshore fields.

In July the NUPRC approved the sale of onshore assets by Eni's local unit to Oando and another from Equinor to new entrant Project Odinmim.

The regulator offered in May faster approvals for pending asset sales by oil majors if they took responsibility for oil spills and compensated impacted communities rather than wait for authorities to apportion liability.

(Reporting by Isaac Anyaogu, Ope Adetayo and Camillus Eboh; Writing by Isaac Anyaogu and Bhargav Acharya;Editing by Alexander Winning and Emelia Sithole-Matarise)