US pharmaceutical giant Pfizer sought damaging information against Nigeria's ex-attorney general to pressure him into dropping lawsuits over a drug trial, a leaked diplomatic cable showed Friday.

According to the cable obtained by WikiLeaks and published by Britain's Guardian newspaper, Pfizer's country manager in Nigeria, Enrico Liggeri, told US officials of the operation in a meeting on April 9, 2009.

"According to Liggeri, Pfizer had hired investigators to uncover corruption links to Federal Attorney General Michael Aondoakaa to expose him and put pressure on him to drop the federal cases," according to the memo, part of the huge trove of documents obtained by WikiLeaks.

"He said Pfizer's investigators were passing this information to local media."

Pfizer reached a 75-million-dollar settlement with the Nigerian state of Kano last year over the 1996 trials with the drug Trovan during a meningitis epidemic.

Nigerian officials alleged the trials, which involved around 200 patients, led to the deaths of 11 children and deformities in dozens of others.

Pfizer has maintained that it committed no wrongdoing and has denied any liability. It has said that Trovan helped save lives.

In addition to the settlement with the state of Kano, federal litigation was also dropped after an agreement was reached, but details remain vague.

In response to the leaked cable, Pfizer issued a statement strongly denying recruiting investigators to probe Aondoakaa, who was removed from his post as justice minister in February.

"Although Pfizer has not seen any documents from the US embassy in Nigeria regarding the federal government cases, any notion that the company hired investigators in connection to the former attorney general is simply preposterous," it said.