Best-selling author Frederick Forsyth, known for thriller novels including The Day Of The Jackal, has died at the age of 86, his agent has said.

"We mourn the passing of one of the world's greatest thriller writers," Jonathan Lloyd said in a statement.

Forsyth published more than 25 books, also including The Odessa File and The Dogs of War, and sold 75 million books around the world, he said.

His publisher Bill Scott-Kerr said: "Still read by millions across the world, Freddie's thrillers define the genre and are still the benchmark to which contemporary writers aspire. He leaves behind a peerless legacy which will continue to excite and entertain for years to come."

Born in Kent in 1938, Forsyth joined the RAF at the age of 18 before becoming a war correspondent for the BBC and Reuters. He revealed in 2015 he also worked for British intelligence agency MI6 for more than 20 years.

Many of his fictional plots drew on his real-life experiences around the world.

He made his name with his first novel, 1971's The Day Of The Jackal, which he wrote when he was out of work.

"[I was] skint, in debt, no flat, no car, no nothing and I just thought, 'How do I get myself out of this hole?' And I came up with probably the zaniest solution - write a novel," he said.

It is a gripping tale, set in 1963, about an Englishman hired to assassinate the French president at the time, Charles de Gaulle.

The Day Of The Jackal was turned into a 1973 film starring Edward Fox as the Jackal, and then became a TV drama starring Eddie Redmayne last year.

Forsyth died on Monday after a brief illness, a statement said.

"We mourn the passing of one of the world's greatest thriller writers," Mr Lloyd said.

"Only a few weeks ago I sat with him as we watched a new and moving documentary of his life - In My Own Words, to be released later this year on BBC One – and was reminded of an extraordinary life, well lived.

"After serving as one of the youngest ever RAF pilots, he turned to journalism, using his gift for languages in German, French and Russian to become a foreign correspondent in Biafra.

"Appalled at what he saw and using his experience during a stint as a Secret service agent, he wrote his first and perhaps most famous novel, The Day Of The Jackal, and instantly became a global bestselling author."

Mr Scott-Kerr said working with Forsyth had been "one of the great pleasures of my professional life".

"The flow of brilliant plots and ideas aside, he was the most professional writer an editor could hope for," he said.

"His journalistic background brought a rigour and a metronomic efficiency to his working practice and his nose for and understanding of a great story kept his novels both thrillingly contemporary and fresh. It was a joy and an education to watch him at work."

Singer Elaine Paige, a friend of Forsyth, said she felt "total sadness" at the news of his death.

"His academic knowledge of places, palaces and geography was bar none," she wrote on X. "He'll be much missed for so many reasons."

English composer Andrew Lloyd Webber, who worked with Forsyth on Love Never Dies, the follow-up to Phantom of the Opera, said: "He really understood the romance and thrills which make the Phantom such an alluring character.

"Thank you Frederick, for creating stories which will live on for generations in your honour."

And Conservative MP Sir David Davis said his "great friend" was a "terrific man" and a "fabulous wordsmith".

"He was a great believer in the old values - he believed in honour and patriotism and courage and directness and straightforwardness and [was] a big defender of our armed forces," he told Sky News.

Forsyth followed The Day Of The Jackal with The Odessa File in 1972, which was adapted for the big screen in a film starring Jon Voight two years later.

The author had written a follow-up, Revenge of Odessa, with fellow thriller writer Tony Kent, which will be published this August.

His other best-selling works included 1984's The Fourth Protocol, which became a film starring starring Michael Caine and Pierce Brosnan.

He was made a CBE for services to literature in 1997.

He had two sons with first wife Carole Cunningham. His second wife Sandy Molloy died last October.