The Duchess of Sussex’s father has appeared in a US court accused of possessing child sex abuse material, including images of himself with naked young girls.

Thomas Markle Sr was arrested by FBI agents on Thursday after the seizure of dozens of items from two Los Angeles storage units he rented for nearly two decades.

He is charged with one count of possession of child pornography.

Markle Sr came under investigation after he was reported to police in the Philippines and the FBI last month by his son, Thomas Markle Jr, who allegedly found illegal images in his father’s belongings in Cebu City.

Mr Markle Jr told The Sun newspaper he had tipped off the authorities about the LA storage facilities.

Acting on warrants, the FBI searched the units registered to Markle Sr which he had rented since 2008, with his most recent payments on both made last month by auto-pay.

Inside agents seized about 78 items, including slides, film negatives, and books that contained suspected child sex abuse material.

Two of the images allegedly depict an adult man – whom a witness “positively identified” as Markle – with a nude young girl.

In one of them, according to court documents, the man “appears to be in the age range of 30s to 40s”, which suggests the alleged abuse dates back decades given Markle is now 82.

A third image is said to show a nude young girl in a room that appears to be part of a motel chain in the Philippines.

Other photographs allegedly show Markle with children in various stages of undress.

If convicted, Markle would face at least 20 years in federal prison.

First assistant US attorney Bill Essayli said: “Mr Markle is accused of possessing child sexual abuse material, including photographs depicting himself with minor girls.

“These allegations are extremely serious, and we will prosecute Mr Markle to the fullest extent of federal law.”

FBI director Kash Patel said: “Mr Markle allegedly targeted innocent children and sought to steal their innocence through his criminal actions.

“Working with our Justice Department partners, our agents moved quickly, identified and located the explicit material, and arrested Mr Markle in Florida.

“This FBI will use every single resource at our disposal to protect innocent kids – any predator who targets children will have zero safe haven in this country or anywhere they try to hide.”

Patrick Grandy, the assistant director in charge of the FBI’s Los Angeles field office, said: “This case highlights the importance of the involvement of the public, even if it’s a family member or close friend, to be vigilant and speak up if they have information on individuals they suspect may be preying on and exploiting our children.”

Markle Sr, who was living in a dementia care home in the US, has admitted paying for sex in the Philippines but has denied ever possessing child abuse imagery.

Meghan, who moved back to the UK with Harry in August, said she was “deeply distressed” at the allegations about her father, from whom she has been estranged since the run-up to her 2018 wedding.

She revealed she was sent a letter via the Metropolitan Police and Royalty and Specialist Protection in 2019 which made “troubling and disturbing allegations” about her father, but she was given assurances these were being investigated.

The Met has admitted it never shared the details with other law enforcement agencies, with the police watchdog, the Independent Office for Police Conduct, now investigating the force’s conduct.

The duchess had wanted to “speak out” immediately after reading the letter but police advised her against this, sources said.

When former TV lighting director Markle Sr had his leg amputated in the Philippines last year, he made pleas for the duchess to contact him.

Meghan is said to have written him a final letter in which she said she knew he was an abuser and that he would never see his grandchildren Prince Archie and Princess Lilibet.