Officials in Nigeria's northern Kano State have ended out-of-court settlement talks with the U.S. drug company, Pfizer, over a 1996 drug trial that allegedly killed 11 children.

Kano Attorney General Aliyu Umar said Wednesday that the state will no longer take part in negotiations with Pfizer, because it was dissatisfied with the way the talks were going.

Kano state is suing the drug company for more than $2 billion. The state and Nigeria's federal government accuse Pfizer of conducting unauthorized clinical trials of the drug Trovan.

They say the trials led to the deaths of 11 Nigerian children and caused permanent health problems for dozens of others.

Pfizer has denied any wrongdoing, and says the alleged victims were affected by meningitis, not Trovan.

The pharmaceutical company says its tests were conducted in an ethical way and with the full knowledge of the Nigerian government.

More than 12,000 Nigerian children died from a 1996 epidemic of meningitis, an infection of the nervous system that can kill a victim within hours.

The federal government also is seeking several billion dollars in compensation from Pfizer. A court hearing the Kano state's case Wednesday adjourned the matter until January 28.

Some information for this report was provided by AFP and Reuters.