The estranged father of Meghan Markle, the Duchess of Sussex, has been jailed after US authorities said he cut an electronic monitoring device off his ankle, days after his arrest for keeping child sexual abuse material in storage units in California.

Thomas Markle, 82, was in custody awaiting a hearing in federal court in Tampa, Florida, first assistant US attorney Bill Essayli said. He was arrested shortly after he cut off the ankle bracelet at 1.45am on Tuesday, Essayli said.

“Release conditions are court orders, not suggestions. We are asking the court to revoke his release and detain him pending trial, and we will continue to prosecute this case to the fullest extent of the law,” Essayli said.

The US magistrate judge Lindsay Griffin agreed on Tuesday that Markle now must be kept in custody.

Markle’s arrest on Friday followed the seizure of approximately 78 items, including slides, film negatives and books that contained suspected child sexual abuse images in storage in the Los Angeles area, Essayli said.

Among the alleged child sexual abuse material were sexually explicit photographs of Markle with underage girls, including one taken in what appears to be part of a motel chain in the Philippines, Reuters reports.

According to the criminal complaint, the special agent investigating Markle’s alleged storage unit said he “viewed a collection of what appeared to be strips of 35mm film negatives seized from Storage Unit 1 registered to Markle”.

“To date, I have identified approximately 18 images that appeared to constitute child pornography,” the special agent noted in the complaint, adding that the investigation remains ongoing.

Markle reportedly had rented the storage units in Los Angeles since 2008, with the FBI noting that the most recent auto-payment for the units was on 14 October.

“Markle’s use of Storage Unit 1 was also corroborated by items found within the unit bearing his name, including boxes labeled ‘Tom Markle’ and an address within the central district of California,” the criminal complaint said.

During his arrest last week, he was taken from a senior care center in Lakeland, Florida, by ambulance. Hours later, a judge allowed Markle to be released on the condition that he be electronically monitored, which typically means wearing an ankle tether.

According to Griffin, Markle’s court appearance last Friday included a “lack of recall”. Griffin also cited Markle’s “health condition” and “advanced age” as part of his appearance.

The judge ordered a mental competency exam and a report by 20 November.

Griffin said she found “reasonable cause to believe” Markle was suffering from a condition “rendering him mentally incompetent to the extent that he is unable to understand the nature and consequences of the proceedings against him or to assist properly in his defense”, CBS reported.

His daughter, Meghan, the Duchess of Sussex, married Prince Harry at Windsor Castle in 2018. They have two children, Prince Archie and Princess Lilibet. She is an American citizen and actor who starred in the US television drama Suits.

Meghan recently said she was “deeply distressed” by allegations that a collection of child sexual abuse images had been found at her father’s former home. She also revealed that a letter containing “troubling allegations” about him had been sent to police in London in 2019.

“It made troubling and disturbing allegations against my father and I was given assurances that these were being investigated,” Meghan said of the letter. “I hope it can now be understood that, despite certain media publications’ distortion over the years, any distance from my father and my choice to not allow him to have contact with our children was for one reason: to protect them.”

Thomas Markle was living in the Philippines this year when he suffered a stroke and had his left leg amputated. That forced him to return to the US.

His arrest followed reports by the Sun, a British tabloid newspaper, that Meghan’s half-brother found a collection of child sexual abuse images while clearing out their father’s home in the Philippines. That discovery led to information about two US storage units in California, which Markle had rented since 2008.

Associated Press contributed reporting