A top campaign aide to embattled US Congressman George Santos has pleaded guilty to conspiracy to defraud.

Nancy Marks, who appeared in court on Thursday, admitted she falsified some of the campaign's financial records.

She reported a fake $500,000 (£410,000) loan that Mr Santos claimed to have given the campaign, prosecutors say.

It is the latest trouble for the Republican lawmaker, who has himself been indicted on several charges.

During her court appearance, Ms Marks told the judge: "I knew that the loan had not been made," the New York Times reported.

The false reports meant the campaign qualified for the fundraising benchmarks needed to receive financial support from the national Republican Party committee.

Prosecutors also say the campaign reported false contributions from at least 10 members of Mr Santos' family.

Ms Marks was arrested on Thursday and entered the plea in federal court in Long Island.

She could face up to four years in prison under her current plea agreement. She was released on an unsecured $100,000 bond.

Her lawyer, Ray Perini, reportedly said Mr Santos had "mentally seduced" his client.

Shortly after Mr Santos' election to represent a suburban New York district in 2022, the New York Times and other outlets reported that he had fabricated significant portions of his resume and life story.

He also faced intense scrutiny for the questionable reporting and use of his congressional campaign funds.

Mr Santos was indicted in May on charges of wire fraud, making false statements to the US House of Representatives, money laundering, and theft of public funds.

He has pleaded not guilty and denies the charges.

Despite facing calls to resign, Mr Santos has continued to serve in Congress and actively courts the spotlight.

He has, however, admitted "embellishing" his resume.