Russia's giant Yukos Oil Co. has offered to pay $8 billion in back taxes, even more than it has been billed so far, as long as it is allowed to pay in installments, but the government has refused to accept the settlement plan, a company executive said Sunday.

The proposal was the latest in a series of proposed deals Yukos has floated in an effort to stave off bankruptcy and keep the government from seizing control of the company or its assets in the politically charged case. Government agents last week began moving to confiscate Yukos subsidiaries and other property.

The new offer, which represented substantially more than any previously proposed settlement put forth by the company, appears to be an attempt to end a process that could drag out for many more months. A Moscow court has ordered Yukos to pay $3.4 billion in taxes and penalties from 2000, but the company said it did not have enough cash to meet last week's deadline.

The government's tax service has also sent Yukos a new audit determining that it owes an additional $3.4 billion from 2001, but the company has yet to be formally ordered to come up with the money. It could contest the audit first with the tax service and then in court. Russia's chief prosecutor has said bills could be sent soon for 2002 and 2003 as well. The company estimated that ultimately all government bills would probably add up to $8 billion.

"Yukos has offered a very reasonable offer even though we've absolutely done nothing wrong," said the Yukos executive, who spoke on condition of anonymity because of the sensitivity of the discussions. "Given the performance of the court system so far, we see that there is no way that we will win."

Under the latest plan, the company would put up its 35 percent share in Sibneft, another oil company, as security for its tax debt, the executive said. Yukos would then pay $2.5 billion to the government this month, another $2.5 billion in a year and the final $2.5 billion in two years. The company would also give up about $550 million in value-added tax refunds it claims it is due.

The government, however, has indicated no interest in the plan. The proposal was made in a letter signed by Yukos's newly appointed chief executive officer Steven M. Theede, an American, and sent to Prime Minister Mikhail Fradkov on Thursday.

On Friday, Finance Minister Alexei Kudrin, commenting to reporters without directly referring to the offer, ruled out any restructuring of the tax debt in principle.

The government has not answered Yukos directly, said Anton Drel, an attorney for the company's imprisoned chief shareholder, Mikhail Khodorkovsky, who previously offered to give up his stake in the company to satisfy the tax claim.

The maneuverings over the fate of the company come as Khodorkovsky is to return to court Monday for hearings leading up to his trial on fraud and tax evasion charges.