Nigeria says the suspect spent very little time at Lagos airport
The Nigerian man accused of trying to blow up a transatlantic airline on Christmas Day began his journey in Ghana, the Nigerian authorities say.
Umar Farouk Abdulmutallab spent just half an hour at the airport in Lagos before transferring to an Amsterdam flight, the information minister said.
It had been assumed the 23-year-old began his journey in Nigeria.
But Ghana has disputed Nigeria's timings, saying Mr Abdulmutallab's stop-over was at least three hours.
A senior Ghanaian government official told the BBC that the suspect bought a one-way ticket to Lagos from Accra that would have given him more than three hours at the airport.
He accused the Nigerians of attempting to "pass the buck" as the search for security lapses continues, the BBC's West Africa Correspondent Caspar Leighton reports from Accra.
Nigeria's Information Minister Dora Akunyili earlier told the BBC that it was now known Mr Abdulmutallab had boarded a Virgin Nigeria plane from Accra to Nigeria, arriving at Lagos' Murtala Muhammed airport on 24 December.
His passport was scanned on entry into Nigeria at 2008 (1908GMT), and again, as he boarded the flight to Amsterdam, at 2035, she said.
Dora Akunyili has defended Nigeria's security procedures
"He was able to connect that fast because he was not checking in any luggage," she said.
From Amsterdam, the Northwest Airlines Flight 253 - with 278 passengers and 11 crew aboard - went on to the US city of Detroit.
Some 20 minutes before landing at the city's Metropolitan Airport, on the afternoon of Christmas Day, Mr Abdulmutallab was spotted by flight crew and passengers trying to ignite explosives strapped to his leg, investigators say.
The explosives failed to detonate, although it is thought they may have caused a small fire which burned the suspect's leg.
He is now in US custody.
The incident has led to a worldwide re-think about security procedures.
US President Barack Obama is reading reports received about the security lapses that led to the near-disaster in Detroit, and intends to meet security chiefs on Tuesday to discuss new measures.
British Prime Minister Gordon Brown announced on Friday he had ordered a review of existing security measures, and would "move quickly" to enhance airport security.
Full-body scanners would be among the new technologies considered, he said.
The Dutch authorities announced earlier this week that body scanners would be used on all passengers flying from Amsterdam's Schiphol airport to the US.
The incident has also thrown the spotlight on Yemen, where Mr Abdulmutallab was living in the months leading up to the attack.
It is feared the troubled country is becoming a major training centre for militants, with several hundred al-Qaeda members believed to be operating there.
In recent weeks, Yemen has launched major operations against al-Qaeda with US backing, but has warned that it needs more Western support to tackle the threat.
Britain's prime minister has called a summit in London to discuss radicalisation in Yemen.
Mr Brown's office said the 28 January event had support from Washington and the European Union, and Mr Brown aimed to attract Saudi Arabia and Gulf states.
Somalia's hardline Shabab group - which controls large swathes of Somalia, including much of the capital Mogadishu - said on Friday it would send fighters to help fellow militants in Yemen.
"We tell our Muslim brothers in Yemen that we will cross the water between us and reach your place to assist you fight the enemy of Allah," said Shebab's Sheikh Mukhtar Robow Abu Mansour.