Mali has suffered a new case of Ebola infection with the death of a nurse who treated a patient from Guinea, according to medical sources.

"The nurse, who had been in contact with a Guinean national who died of the illness, died in turn," said an official at the Pasteur Clinic in the capital Bamako, where the male nurse worked.

Tests had confirmed the presence of the Ebola virus, the official added.

The government said that all necessary steps to identify people who had come into contact with the nurse had been taken.

It did not say how many people were being traced.

The clinic where the patient was treated is now in lockdown and a doctor there is suspected of having contracted the deadly virus, according to officials.

Around 30 people are locked in the quarantined building.

The people trapped in the Pasteur clinic include 15 African UN soldiers being treated for injuries and tuberculosis, a security source told AFP.

"A doctor who is actually a suspected case of Ebola is under observation, because he has been in contact with the two dead people, and we are searching for others who were around the deceased but returned home," an official at the clinic said.

The first victim was a two-year-old girl from Guinea who was diagnosed with Ebola after journeying to the western town of Kayes on 23 October. She died the following day.

The toddler had travelled by bus and taxi with her grandmother, sister and uncle, making frequent stops on a trip of more than 1,200km.

They also spent two hours in the capital Bamako, visiting relatives in a house of 25 people.

The largest Ebola outbreak on record has killed about 5,000 people, mainly in western Africa, with Liberia hit hardest and the contagion still raging in neighbouring Sierra Leone and Guinea.

Liberia has announced a dramatic drop in new Ebola infections, but the latest Ebola death in Mali brings fresh concerns of further contamination.