Author Tom Clancy, 66, died at John Hopkins Hospital in Baltimore, MD. on Tuesday, according to multiple reports.

Clancy is the writer behind bestselling military inspired novels "The Hunt for Red October," "Patriot Games" and "Rainbow Six".  His books were made into films and were the inspiration behind the "Splinter Cell" video games.

The cause of Clancy's death has not been confirmed.

"Seventeen of his novels were No. 1 New York Times best sellers, including his most recent, 'Threat Vector,' which was released in December 2012," the New York Times reports.  "More than 100 million copies of his books are in print."

The writer's characters have been portrayed by many Hollywood heavyweights.

"Clancy's most famous character was CIA agent Jack Ryan -- who was portrayed on the big screen by actors like Alec Baldwin, Harrison Ford, and Ben Affleck. Chris Pine is set to play Ryan in the upcoming movie, 'Jack Ryan: Shadow One'," TMZ reports.

Clancy was reportedly accused of using classified information for his novels, since it was well known he spent time with high-ranking military officials, visited military bases and the Pentagon, according to the Times. 

However, Clancy denied having any access to classified documents and using them to write his bestselling books.

"I hang my hat on getting as many things right as I can," Clancy once told the Times. "I've made up stuff that's turned out to be real - that's the spooky part."

He leaves behind his wife, their daughter and four other children from previous marriages.

"When he published 'The Hunt for Red October' he redefined and expanded the genre and as a consequence of that, a lot of people were able to publish such books who had previously been unable to do so," Stephen C. Hunter, an author and former Pulitzer Prize-winning film critic for The Washington Post, told the Baltimore Sun. "He valued technical precision and on-target writing that became the form of the modern thriller."