Stephen King has apologised for calling a fatal crash between a lorry and a train carrying Republican lawmakers “karma”.

The horror and science fiction author admitted he had been “thoughtless” to tweet a joke about the collision, which killed one person and seriously injured another in rural Virginia.

His initial post sparked outrage on social media, where his comments were described as “vile” and “crass”.

Dozens of Republican members of Congress, including House Speaker Paul Ryan, were travelling from Washington to their legislative retreat in West Virginia when their train crashed into a dustbin lorry that was crossing railway lines on Wednesday.

A passenger in the truck died and its driver was seriously injured. No Republicans or their families, who were also travelling on the train, were badly hurt.

The next day, Mr King, a vocal critic of President Donald Trump, tweeted: “A trainload of Republicans on their way to a pricey retreat hit a garbage truck. My friend Russ calls that karma.”

After being criticised for the post, he added: “Of COURSE sorry the truck driver died.”

He later followed up with a longer apology, writing: “A rather thoughtless tweet from me concerning the train-truck crash, for which I apologise (if one is necessary). It should be pointed out, too, that those Republican politicians, who can be heartless when they vote, immediately got out to help.”

Piers Morgan was among the many people who criticised the writer's initial tweet, responding: “A man died in that crash, you despicable man.”

Others said they would consider boycotting the King’s books over his comments.