Prosecutors in the United States have charged two Swiss executives with paying secret kickbacks to Iraq in the United Nations oil-for-food programme.
Criminal investigations are also underway in Switzerland into several people suspected of illegal dealings in connection with the programme.
The New York justice authorities said on Friday they were seeking the extradition of two Swiss nationals, Catalina del Socorro Miguel Fuentes and Mohammed Saidji.
A third suspect, prominent Texas oil tycoon Oscar Wyatt was arrested on Friday. All three face up to 62 years in prison and heavy fines if convicted.
Three companies were also charged, including the Cyprus-based oil trading companies Nafta Petroleum Company and Mednafta Trading Company, collectively known as the Wyatt Foreign Companies.
Those firms were operated by Miguel and Saidji in close consultation with Wyatt, the statement said.
Also charged was Sarenco, a Swiss consulting firm operated by Miguel and Saidji, prosecutors added.
"Wyatt, Miguel and Saidji obtained oil under the United Nations' oil-for-food programme by paying millions of dollars in secret kickbacks to Saddam Hussein's regime in Iraq.
"These kickbacks were allegedly paid to the government of Iraq for oil allocated by the Saddam Hussein regime to the Wyatt Foreign Companies and the Coastal Corporation," prosecutors said.
They allege that Wyatt, Miguel and Saidji directed millions of dollars in illegal kickbacks to Saddam's government by depositing cash into a Jordanian bank account.
A flamboyant personality in a typically conservative oil industry, Wyatt has had close ties with Iraq for years.
Federal prosecutors in New York have now charged six people and six companies involved in the programme, and state prosecutors have pursued their own cases.
Switzerland opened criminal investigations into several people suspected of illegal dealings with the UN programme for Iraq.
In April the Federal Prosecutor's Office said the inquiry focused on active bribery and money laundering in connection with suspicious flows of money.
The Office added that three suspects had been identified, but gave no further details.
The now-defunct oil-for-food programme allowed Saddam to sell oil to buy food and medicine in order to ease the impact of UN sanctions. It ran from 1996 to 2003.
Under the programme Iraq was able to negotiate its own contracts, and mismanagement allowed Saddam to rake in more than $10 billion (SFr12.9 billion) in oil smuggling profits, according to the US Central Intelligence Agency (CIA).
An investigation led by former US Federal Reserve Chairman Paul Volcker found that Secretary-General Kofi Annan, his deputy and the UN Security Council all share responsibility.
Volcker announced on Friday he would issue a final report next week on the role of private companies in the scandal. It is believed that there is evidence of wrongdoing among some 2,500 of the more than 4,000 firms involved in the programme.
swissinfo with agencies
The "oil-for-food" programme ran from 1996 to 2003. Its aim was to allow the Iraqi governemnt to export crude oil to import essential goods.
The regime of Saddam Hussein undermined the system with the cooperation of foreign companies. The US suspect Saddam cashed in more than $10 billion (SFr12.9 billion) in smuggling profits.
In September an independent inquiry found that UN Secretary-General Kofi Annan, his deputy and the UN Security Concil share responsiblity by turning a blind eye to corruption and mismanagement in connection with the "oil-for food" programme.