The Nigerian Government says it has written to the Italian Embassy asking it why the 26 migrants recovered from the Mediterranean were buried nine days before the agreed date.
The Senior Special Adviser to the President on Foreign Affairs and Diaspora, Abike Dabiri-Erewa, told a news conference in Abuja on Monday that three bodies were identified as Nigerians.
Mrs. Dabiri-Erewa said that time was not given for adequate identification of the girls and feedback on investigations carried out by the relevant authorities in Italy adding that the government would investigate at the "highest diplomatic level".
"It was shocking to watch the burial of these migrants on television, I think on November 17, because the information from the Italian Embassy to National Agency for Prohibition of Trafficking in Persons (NAPTIP) was the fact that these girls would be buried on November 26.
"We are asking the Italian authorities, and we have communicated a letter through the Italian Embassy here in Nigeria, why these girls were buried nine days before the agreed date.
"Secondly, where are the results of the pathological tests that were done, who conducted the DNA tests and how do we now identify that all 26 girls were Nigerians?
"From available information coming from Italy as I speak, about three girls can be identified to be Nigerians.
"Did Italy get the permission to go ahead with the burial of these girls no matter their nationalities?
"We appeal to the Italian authorities, we are going to take this up at the highest diplomatic level and we are going to get answers."
She said that 64 migrants were involved in the accident with many bodies unaccounted for and more questions to be answered by the Italian authorities.
She added that the Director-General of NAPTIP was currently in Italy working out further communications on the next step to take.
"The fact is at the other end, they are not willing to save irregular migrants any more so it is going to get tougher and dangerous.
"Yes, the administration should do the needful but the most important thing is awareness."
A representative of NAPTIP, Abdulrahim Shaibu, Director, Legal and Prosecution, said that the burial of the 26 dead migrants was a violation of agreements shared by both countries.
"Between Nigeria and Italy, we have a Memorandum of Understanding and a cooperative agreement with anti-mafia; they are supposed to give us all information concerning our victims as well as any trafficker they get.
"On this particular issue, we relied on their information that these girls would be buried on November 26 and this is in violation of the agreement to exchange pre-information so our government will have to take it up."
Mr. Shaibu also said that the agency was doing a lot to sensitise Nigerians to the dangers of human trafficking.
"This mishap is one to many and that is why we are asking state governments to back our efforts and create programmes that would involve the youths to engage them productively."
The bodies of the 26 migrants were discovered on the Mediterranean by a Spanish Warship, Cantabria on November 5 and were all females from the ages of 14 to 18.
A funeral was, however, held for them in Salerno, Italy on November 17.