The Nigerian government has accused a Chinese company of mounting a campaign to seize its assets overseas, including presidential jets, a government spokesperson said on Thursday.

Presidential spokesperson Bayo Onanuga said Zhongshan Fucheng Industrial Investment Co. Ltd. is using "unorthodox means" to target Nigerian government property, despite having no contractual obligations with the federal government.

Zhongshan did not immediately respond to a request for comment.

The dispute stems from a 2007 contract between Zhongshan and Nigeria's southwestern Ogun State to develop a free trade zone, which was terminated in 2015.

Onanuga said when the Ogun State contract was revoked in 2015, Zhongshan had done no more than erect a perimeter fence on the land earmarked for the free trade zone.

"Zhongshan has no solid ground to demand restitution from the Ogun State Government based on the facts regarding the 2007 contract between the company and the State Government to manage a free-trade zone," Onanuga said in a statement on Thursday.

Nigeria's national government said it is not a party to the contract and that Zhongshan has misrepresented facts to courts in the UK, the United States, and also in France, where it secured more than $60 million in an arbitration award. Nigeria has declined to pay up, Onanuga said.

Onanuga said that Zhongshan obtained two orders from a French court in March and August to seize Nigerian assets, including presidential jets undergoing maintenance in France. He said these assets are immune from foreign legal actions.

The Nigerian government is working with Ogun State to resolve the dispute and protect the country's assets from seizure, Onanuga said.