"Technical difficulties" have delayed Nigeria's transfer of the disputed oil-rich Bakassi peninsula to Cameroon, says Nigeria's defence minister.
Most Bakassi residents consider themselves to be Nigerian
The handover was due to take place on Wednesday, under a 2002 ruling by the International Court of Justice (ICJ).
But Rabiu Musa Kwankwaso said working out the finer details of the sea border was stalling the handover.
He played down public opposition to the handover of the peninsula, which is home to thousands of Nigerians.
The minister said the joint boundary commission, set up by Cameroon and Nigeria to implement the ICJ ruling, was working very hard to finish the border demarcation.
"I don't think I should give a date now," Mr Kwankwaso told the BBC's Network Africa programme in response to when the commission will finish its work.
"I am very much aware that the commission is working very hard to finish the technical aspects of the job so that we can put that problem behind us."
The minister denied speculation that the postponement was because the peninsula, which juts into the Gulf of Guinea, is oil-rich.
On Tuesday, Nigeria's parliament reaffirmed that the territory could not be given to Cameroon without a constitutional change.
"We will do everything possible to keep Bakassi as part of Nigeria," parliament spokesman Farouk Adamu Bello told the BBC.
Mr Kwankwaso said his government was "very much interested in what is happening to Nigerians... those in Bakassi and elsewhere" and said the two governments are talking at the highest levels.
Take up arms
Earlier, UN negotiator Ahmedou Ould Abdallah said that any delay did not mean Nigeria had officially challenged the ICJ ruling, which remains binding.
Local political leaders have been lobbying the Nigerian government to delay implementing the ruling and have called for a referendum in Bakassi.
The inhabitants of the peninsula are adamant that they do not want to live under Cameroonian rule and some say they are ready to take up arms to avoid this.
After border clashes in the 1990s, the territory was awarded to Cameroon as part of an ICJ ruling that was based on a 1913 colonial agreement.
The border commission has so far over seen the transfer of 33 villages along the northern land boundary to Cameroon, while two Cameroonian villages have been given to Nigeria.
Nigerian President Olusegun Obasanjo agreed to abide by the ICJ ruling.