US authorities continue to dig into Fifa corruption with a subpoena against Citigroup. Getty

Marking banks as the next major focus in America's sweeping investigation into Fifa corruption, US federal authorities have slapped a subpoena on Citigroup demanding details of transactions linked to alleged crimes involving the international soccer association.

The US Attorney for the Eastern District in New York, which is leading the case against Fifa graft, is seeking any information related to "banking relationships and transactions" tied to individuals and entities "identified as having had involvement with the alleged corrupt conduct" outlined in the 2015 indictments against FIFA leaders and executives of sports marketing corporations, Citigroup revealed in a regulatory filing.

Citi is the first major US bank to reveal that it has been subpoenaed in the probe.

In October 2015 Credit Suisse revealed that officials were grilled by US and Swiss authorities concerning the bank's potential involvement in money-laundering schemes.

A statement from Citi said officials are "cooperating" with authorities on the subpoena.

Fifa officials used several US banks — including Citi, JPMorgan and HSBC — in the transfer of up to $150 million (£107m) in bribes and kickbacks, according to the slew of indictments issued against Fifa leaders and executives from sports marketing corporations. US law requires financial institutions to report suspicious transactions to authorities.

The feds filed an initial 47-count indictment against 14 Fifa and corporate leaders in May 2015, then added another 92-count superseding indictment against another 16 individuals in December.

Authorities clearly signaled their interest in possible bank involvement in Fifa corruption with a special section in the December indictment headlined "The Centrality of the US Financial System."

Throughout the 1990s up to 2010 defendants and their "co-conspirators relied heavily on the United States financial system in their connection with their activities," notes the indictment. "This reliance was significant and sustained and was one of the central methods and means through which they promoted and concealed their schemes."

The document ticks off a list of transactions involving suspected bribes at major banks in Switzerland, New York and Florida.

Citibank was mentioned 15 times in the original indictment against Fifa.

According to the initial indictment after Qatar won the vote making it the controversial host of the 2022 World Cup, $1.2 million (£86,000) was deposited from Qatar into a Citibank account controlled by former Fifa Executive Committee member Jack Warner. The one-time head of Concacaf — the Fifa member association representing North and Central America and the Caribbean — is facing several major criminal charges for bribery and money laundering, and has been banned from Fifa for life.

Warner's sons, Daryll and Daryan Warner, have been cooperating with federal authorities since 2013. Daryll was nabbed frantically depositing over $100,000 in suspicious funds in increments of less that $10,000 in various branches of a New York bank to avoid reporting the deposits to the tax man.