NEW YORK (CNN/Money) - Federal prosecutors have demanded during plea negotiations that former ImClone CEO Samuel Waksal serve a 7- to 10-year prison term for charges related to insider trading and are not willing to let his family members get off easy, a source close to the situation confirmed to CNN/Money Tuesday.

Prosecutors also want Waksal to admit guilt for allegedly selling shares of company stock and encouraging family and friends to do the same after he learned that the Food and Drug Administration would refuse to consider ImClone's cancer drug application, the source confirmed following a report Tuesday in the Wall Street Journal.

But sources close to the situation told the Journal Waksal has argued the demands are too harsh and is still fighting to keep his family from being indicted, the report said.

Prosecutors think they have enough evidence to charge Waksal and one of his daughters with selling the ImClone shares before an announcement of the drug application's fate was made to the public.

Officials with the U.S. Attorney's office in New York were not available for comment Tuesday. A spokesman for Waksal declined to comment on the matter.

The judge has extended the deadline for an indictment of Waksal twice and the former CEO's lawyers are expected to make a counter-proposal in the next 10 days.

Waksal is up against six counts of securities fraud, two counts of conspiracy and one count of perjury and could face up to 75 years in jail if convicted of the crimes, the report said.