Four South Africans who are seeking billions of dollars in compensation from US and Swiss corporations for the "blood and misery" which they allegedly caused by doing business with the apartheid regime have filed their suit in New York.

We want reparations from those international companies and banks that profited from the blood and misery of our fathers and mothers, our brothers and sisters

Lulu Petersen, plaintiff

A team of American and South African lawyers is seeking $50bn in damages from class action suit against Citigroup Inc, UBS and Credit Suisse because of the financial backing they offered the former apartheid regime.

The plaintiffs allege that the corporations have profited from loans to the white South African government between 1985 and 1993 while a United Nations embargo was in force.

Lawyers for the plaintiffs hope hundreds and thousands of people will join the class-action case.

A special telephone hotline has been set up in South Africa for victims who want to join the case.

Plaintiffs and allegations

Lulu Petersen: 13-year-old brother killed by police Sigqibo Mpendulo: twin 12-year-old sons killed during a police raid Lungisile Ntsebeza: detained, tortured and banished Themba Makubela: banished

The lawyers plan to argue that the banks helped prop up the apartheid regime with loans and other business deals worth billions of dollars, even after the country was under a UN embargo.

One of the senior lawyers in the case, Professor Dumisa Ntsebaze, told the BBC on Monday: "The multinationals and banks knew that the UN had condemned apartheid as a crime against humanity.

"We believe that there is a statute in the US that can be used by any person to proceed against people that have been complicit against crimes against humanity."

Heckled

A spokesman for UBS said it considered the case to be totally without merit and added that the bank would fight with every means available.

In Switzerland on Monday, the US lawyer Ed Fagan, who is leading the case, was heckled as he arrived to present details of his lawsuit.

Mr Fagan has angered the Swiss in the past.

In 1998 he represented Holocaust victims and their relatives in a $1.25bn settlement against the Swiss banks, triggering widespread international criticism of Switzerland's record during World War II.