Interstate Commerce Commission official Richard Kyle, who resigned on Tuesday rather than face firing on misconduct charges, yesterday angrily withdrew his resignation and decided to fight the charges.

He was promptly fired.

Kyle wrote a three-page letter to ICC Personnel officer Richard H. Mooers yesterday lambasting the commission for breaking its promise not to reveal any of the charges if he would resign. He said it was also agreed that the charges "would not be a part of my personnel file."

Kyle had been earning about $40,000 as deputy director for congressional affairs at the ICC.

But, Kyle pointed out in his letter, news reports of his resignation included statements from ICC officials that he would have been fired had he not resigned.

The Washington Post story also said that the charges against Kyle included allegations that he had accepted "hundreds of dollars" worth of gifts and entertainment from regulated carriers and that he had subsequently lied to ICC investigators looking into the matter.

Kyle and his boss, Robert Oswald, the former ICC secretary and congressional liason officer, are still under investigation by the Justice Department in its probe into alleged influence peddling and mob contact by ICC employees.

Both Kyle and Oswald were placed on administrative leave with pay one year ago after it was revealed they were under investigation by the Justice Department. Last September, however, they were reinstated in what ICC officials called "less sensitive positions" pending the outcome of internal ICC investigations into their activities.

Oswald was fired in December after he was presented with a detailed report outlining allegations against him resulting from the internal probe. Among other things, he was charged with arranging for attorneys to represent certain carriers before the ICC and attempting to get a witness to lie to the Justice Department about a meeting between Oswald and New York mob figure and trucking firm owner Thomas Gambino.

But unlike Oswald, Kyle had agreed to cooperate with the ICC internal investigation, causing several ICC officials to speculate that Kyle's fate would be different than Oswalds. But as it became apparant that Kyle was linked to some of the charges against Oswald, investigators say Kyle lied to them.

Kyle, 51, said in yesterday's letter that "since my reasons for resigning were the direct result of the harassment and coersion to which I have been subjected and my wish to avoid any further adverse publicity was not successful, I am prepared to respond to any charges the commission may wish to bring against me. I am confident that I will ultimately be vindicated."

The ICC responded yesterday stating that it "gave notice that it proposes to terminate the employment of (Kyle) following withdrawal of his resignation."

The ICC could not officially detail the charges because of restrictions imposed by the Privacy Act.

ICC spokesman Douglas Baldwin said the Kyle would have 15 days to respond to the charges outlined against him i na letter from the commission. His separation would come 15 days after that if his appeal is denied.

In another development yesterday, several ICC officials expressed shock when they learned that Oswald, who is 43, had been granted his petition for early retirement disability benefits for what had earlier been described as "lung and stomach problems, including continuing ulcerations."

Despite the fact that he was fired, Oswald was still granted an estimated $17,000 a year by the Civil Service Commission, which yesterday said that the disability benefits "are an entirely different matter," than the ongoing investigation.

"Even if he is indicted and convicted by the Justice Department," one Civil Service spokeswoman said, "he would still get the benefits."

Although Civil Service officials could not disclose the true nature of the disability under the Privacy Act restrictions, they emphasized that they had "thoroughly checked out the disability, and found it to be legitiate."