Federal Savings Bank Chairman and CEO Stephen Calk tried to exchange $16 million in loans to Paul Manafort for a top position within President Donald Trump's administration, according to an indictment unsealed Thursday.

Calk approved millions in "high-risk loans in an effort to secure a personal benefit, namely to an appointment as Secretary of the Army, or another similar high-level position in the incoming presidential administration," Deputy U.S. Attorney Audrey Strauss of the Southern District of New York said.

Federal investigators were probing last year whether Manafort, the former Trump campaign chair, promised Calk a job in the White House in return for the $16 million in home loans, NBC News first reported in February 2018.

Calk, who surrendered to the FBI on Thursday morning, allegedly approved the multiple high-risk loans for Manafort, who urgently needed them to avoid foreclosure. While the loans were pending approval, Calk allegedly provided Manafort with a ranked list of positions he desired. At its head were the two top positions at the U.S. Treasury, followed by secretary of Commerce and secretary of Defense. The list also included 19 high-level ambassadorships, among them ambassador to the United Kingdom, France, Germany and Italy.

Manafort received three separate loans in December 2016 and January 2017 from Federal Savings Bank for homes in New York City, Virginia and the Hamptons, New York. The three loans were questioned by other officials at the bank, two sources with direct knowledge of the matter told NBC News last February.

The loans raised red flags at the bank in part because of Manafort's history of defaulting on prior loans, and because the size made Manafort's debt the single largest lending relationship at the bank, according to prosecutors. Calk was required to authorize an unusual lending scheme to avoid passing the lending cap to a single borrower.

In exchange, Manafort provided Calk with personal benefits, prosecutors said. He was appointed to Trump's Council of Economic Advisers in August 2016, just days after the bank approved a proposed $9.5 million loan to Manafort.

According to the indictment, Manafort and his son-in-law, Jeffrey Yohai, approached the bank in an effort to refinance loans tied to a construction project in Los Angeles.

During a meeting held July 27, 2016 — while Manafort was Trump campaign chairman — Calk allegedly broached the idea of him joining the Trump campaign. By the next day, the first loan of $5.7 million was approved. Less than a week later, Manafort offered Calk a position on the economic advisory committee for Trump, according to the indictment.

Calk issued another loan for more than $9 million later in the fall of 2016. Then, Calk reached out to Manafort asking him if he was involved in the Trump presidential transition following the election, according to the indictment.

Manafort allegedly responded, "total background but involved directly."

Shortly after the election, in November or December 2016, Manafort recommended Calk for an administrative position, leading to a formal interview of Calk for undersecretary of the Army at the transition team headquarters in Trump Tower in 2017. When Manafort made the recommendation, he had more than $6 million in loans pending approval at Calk's bank.

Calk ultimately was not hired for the position.

Months later, the loans to Manafort were downgraded by the bank's regulator, the Office of the Comptroller of the Currency. Calk allegedly lied to regulators, telling them he never desired a position in the presidential administration.

A Nov. 14, 2016, email Calk sent to Manafort that included his résumé and a list of desired positions in ranked order was an exhibit in Manafort's August 2018 trial in Virginia. At the trial, Manafort was convicted by a federal jury on eight felony counts — five counts of tax fraud, one count of failure to file a report of foreign bank and financial accounts and two counts of bank fraud. He was sentenced in March 2019 and is now serving 7.5-year sentence in federal prison.

Rep. Elijah Cummings called the indictment "the latest example of the President’s inner circle trying to make backroom deals to enrich themselves instead of working on behalf of the American people." Cummings, who is chairman of the House Committee on Oversight and Government Reform, began requesting documents related to the allegations from Calk and the Department of Defense in early 2018, after NBC News first reported the probe.

CORRECTION (May 23, 2019, 1.30 p.m. ET): An earlier version of this article misstated Calk's title. He is chairman and CEO, not president.