SANA, Yemen — A senior official here said Thursday that the young Nigerian man accused of trying to bring down an airliner as it was approaching Detroit on Dec. 25 had met with operatives of Al Qaeda and probably with Anwar al-Awlaki, a radical American-born Internet preacher, in Yemen before setting out on his journey.
But the official, Rashad al-Alimi, the deputy prime minister for national security and defense, cited Yemeni investigations and said that the Nigerian, Umar Farouk Abdulmutallab, 23, had acquired the explosives used in the failed attack not in Yemen, which he left on Dec. 4, but in Nigeria. There he changed planes at the Lagos airport on Dec. 24, boarding a flight to Amsterdam and then another to Detroit.
Mr. Alimi’s remarks, made at a news conference in Sana, offered Yemen’s most definitive public reconstruction of Mr. Abdulmutallab’s movements before the attack. But the account differed on crucial points from those given by British, Ghanaian and Nigerian officials: where Mr. Abdulmutallab was recruited, where he obtained the explosives, even how long he spent in the Nigerian airport.
According to previous accounts, Mr. Abdulmutallab flew from Accra, Ghana, on Dec. 24, and had a layover at the airport in Lagos on his way to boarding the Detroit-bound Northwest Airlines flight in Amsterdam. American officials have said that Mr. Abdulmutallab told F.B.I. investigators that Al Qaeda in Yemen had trained him and furnished him with the sophisticated bomb he concealed in his underwear.
Mr. Alimi denied emphatically that Mr. Abdulmutallab left Yemen with the explosives, saying the suspect obtained them in Nigeria, though he offered no specific evidence for his assertion.
The Yemeni official also said that Mr. Abdulmutallab had been recruited in London; British officials have said that they knew he had met with extremists there, but that he was not seen as a threat.
It was unclear how Mr. Abdulmutallab would have acquired the explosives in Nigeria. Nigerian officials have said that he spent less than 30 minutes at the airport and went through the requisite security checks. But the Lagos airport is also known for its corruption and chaos, and officials in Ghana dispute the Nigerian account, saying Mr. Abdulmutallab spent nearly four hours in Lagos before leaving.
Investigators in many countries are seeking clarity on Mr. Abdulmutallab’s movements in the months and weeks before the attack.
The broad timeline offered by the Yemeni official meshes with previously established outlines of Mr. Abdulmutallab’s travels: he went to Sana to attend Arabic language classes last August, was driven to the airport on Sept. 21 with an exit visa but then slipped out of sight.
Mr. Alimi said that before the Nigerian left Yemen, on Dec. 4, he went to Shabwa Province, a remote, rugged area in central Yemen. There, Mr. Alimi said, Mr. Abdulmutallab met with “Al Qaeda elements” and probably with Mr. Awlaki.
Mr. Alimi said that the meeting was in a building that was bombed later, on Dec. 21, by Yemeni forces, while another Qaeda meeting was under way. “This place is indeed associated with Anwar al-Awlaki,” Mr. Alimi said.
Mr. Alimi did not rule out that Mr. Abdulmutallab might have traveled through other remote areas of Yemen. He said British and American intelligence services had not warned the Yemeni authorities about any security concerns relating to Mr. Abdulmutallab before the attack.
Mr. Awlaki’s calls for holy war resonate among Qaeda sympathizers. He exchanged e-mail messages with an American Army officer, Maj. Nidal Malik Hasan, accused of a shooting rampage at Fort Hood in Texas, where 13 people were killed in November.
Mr. Abdulmutallab flew into Ghana from Addis Ababa, the Ethiopian capital, on Dec. 9, according to Ghanaian officials. His subsequent airline tickets were bought there, with cash.