Patrick Sawyer, 40, a Liberian consultant for the finance ministry collapsed on Sunday shortly after arriving in Lagos. Nigeria health minister Onyebuchi Chukwu confirmed Friday that Sawyer tested positive for the deadly Ebola virus, and stated he died while in quarantine.

The test results were validated by other laboratories outside Nigeria, Reuters reported.

"His blood sample was taken to the advance laboratory at the Lagos university teaching hospital, which confirmed the diagnosis of the Ebola virus disease in the patient," Chukwu told a press conference on Friday.

But Lagos city health commissioner Jide Idris contradicted Chukwu's statement, saying officials were still uncertain of Sawyer's cause of death, pending response from a laboratory in Dakar. 

Meanwhile, Lagos government officials maintained Sawyer did not enter the city of Lagos, since he was immediately isolated in the airport for quarantine. He voluntarily turned himself in to authorities and reported severe vomiting and diarrhea. He seemed aware of the situation, as he avoided contact with the general public. Sawyer was visiting Lagos to attend an international conference in the southern city of Calabar, AFP reported.

It is unknown why the health minister and commissioner issued contradicting reports, but Nigeria finance minister Amara Konneh thought that Sawyer died of Ebola because his sister died three weeks ago and tested positive of the deadly virus.

The World Health Organization has recorded 1,093 cases of Ebola with 660 fatalities as of July 20. Health officials worry that it will pose a great problem if the virus spreads in Lagos, the largest city in sub-Saharan Africa.