A company that was awarded more than nine billion dollars in an arbitration case against Nigeria has been ordered by a court in the capital city of Abuja to forfeit its local assets to the government.

The order comes after two men linked to the company, Process & Industrial Developments (P&ID), pleaded guilty to charges of fraud and tax evasion on its behalf, the court said on Thursday.

The impact on the British Virgin Islands-based firm and its international arbitration award, now worth some 20 percent of Nigeria's foreign reserves, was not immediately clear.

Nigeria's Economic and Financial Crimes Commission (EFCC) brought 11 individual charges against P&ID and its local subsidiary. The two men, Muhammad Kuchazi and Adamu Usman, plead guilty to all the charges on behalf of the company.

The men, both Nigerians, were not personally charged and freely left the court.

In a statement, P&ID said the EFCC investigation had not afforded basic human rights to those involved and called on the government to "accept its responsibilities under the law."

"None of the individuals involved are current employees or representatives of P&ID," the spokesman said. "P&ID itself has received no communication from any Nigerian authority about the investigation or today's hearing. There has been no evidence produced, no defence allowed, no charges laid, no due process followed," it said.

The EFCC described Kuchazi as commercial director and Usman as director of the company's local subsidiary.

The men could not immediately be reached for comment.

P&ID was set up to execute a 2010 deal with the Nigerian government to build and operate a gas-processing plant in the southeastern port city of Calabar. When the deal collapsed, P&ID took the government to arbitration, eventually winning a $6.6bn award that has been accruing interest since 2013.

Last month, a judge in London said he would grant P&ID the right to convert the award to a judgment, which would allow it to seek to seize assets from the Nigerian government to collect the award.

The government has said the deal was designed to fail and called the award "an assault on every Nigerian and unfair."

The ruling in Abuja would not necessarily affect P&ID's efforts to seize assets. A Lagos court ordered in 2016 that the entire arbitration be set aside, but the arbitration tribunal rejected the court's jurisdiction to rule on the matter - a decision affirmed by last month's London ruling.

With interest payments, the arbitration award now tops nine billion dollars.

Al Jazeera