The crucial tip-off that led to the discovery of parcel bombs on two cargo planes came from a repentant al-Qaeda member, UK officials say.
Jabr al-Faifi handed himself in to authorities in Saudi Arabia two weeks ago, the officials told the BBC.
The US says its main suspect in the failed bomb plot is the chief bombmaker for al-Qaeda's Yemeni branch.
Yemeni officials said 14 suspected al-Qaeda members had surrendered in the restive southern province of Abyan.
Abyan's governor said five senior figures were among those who had handed themselves in, and more fighters were expected to surrender in the coming days.
Yemen is facing mounting multi-national pressure to battle al-Qaeda, says the BBC's Lina Sinjab in Sanaa, but some doubt its ability to do so as it faces social, economic and political problems at home.
US intelligence officials have suggested the Saudi bombmaker Ibrahim Hassan al-Asiri, said to be in his 20s, is the key suspect in last week's attempt to send the parcel bombs from Yemen to the US.
One bomb travelled on two passenger planes before being seized in Dubai. The other almost slipped through Britain, and UK authorities have been criticised for their initial failure to find the bomb on a plane at East Midlands airport.
UK Home Secretary Theresa May said the device was probably intended to detonate mid-air, and has announced a review of all aspects of the UK's air freight security, as well as restrictions on the transportation of ink cartridges.
She was addressing parliament after Prime Minister David Cameron chaired a meeting of the government's emergency planning committee, Cobra.
The UK has already stepped up its air freight security, suspending cargo and passenger flights from Yemen.
Mrs May said cargo flights from Somalia would also be suspended due to suspected links between militants in the two countries.
"From midnight tonight we will extend the suspension of unaccompanied air freight to this country not just from Yemen but also Somalia," she said.
Jabr al-Faifi is reportedly one of several former detainees at the US detention centre at Guantanamo Bay, Cuba, who were returned to Saudi Arabia for rehabilitation in December 2006.
After leaving Guantanamo he went through a rehabilitation programme in Saudi Arabia and then rejoined al-Qaeda in Yemen before turning himself in to Saudi authorities, AFP news agency reports.
He contacted Saudi government officials saying he wanted to return home and a handover was arranged through Yemen's government, interior ministry spokesman General Mansour al-Turki said.
Both bombs used in the latest plot were hidden inside printer toner cartridges and contained the powerful plastic explosive PETN, which is difficult to detect.
John Brennan, counter-terrorism adviser to US President Barack Obama, said the devices were built by the same man who made the explosive device containing PETN that was used in a failed "underpants" plane bomb attack over Detroit on Christmas Day.
One of the detonators was reportedly almost exactly the same as the one used in the US attack attempt.
"[The bombmaker] is a very dangerous individual - clearly somebody who has a fair amount of training and experience," Mr Brennan told ABC News.
"We need to find him and bring him to justice as soon as we can."
Asiri is believed to have built the bomb that his brother, Abdullah, used in an assassination attempt on the Saudi intelligence chief, Prince Mohammed Bin Nayif. The prince survived the suicide attack, in which PETN was also used.
BBC security correspondent Frank Gardner says most of al-Qaeda in the Arabian Peninsula's more dangerous operatives are Saudis, driven out of their own country by a highly effective counter-terrorism campaign that has not yet been matched in Yemen.
Mr Brennan said the US and its allies could not assume that there were no other packages containing bombs out there.
"What we are trying to do right now is to work with our partners overseas to identify all packages that left Yemen recently, and to see whether or not there are any other suspicious packages out there that may contain these [Improvised Explosive Devices]," he told ABC.
Yemeni flights banned
The two packages were shipped from Sanaa through UPS and another US cargo firm, FedEx. The parcels were addressed to synagogues in the US city of Chicago.
One device was carried on an Airbus A320 from Sanaa to Doha. It was then flown on another aircraft to Dubai, Qatar Airways said.
Meanwhile, Germany has announced a ban on all passenger and cargo flights from Yemen.
That makes Italy the only western European country still allowing direct passenger flights from Yemen - a total of two Yemenia Airways flights a week.
Most flights leaving Yemen travel to Saudi Arabia, UAE and Egypt.
Yemen's Minister of Transport Khalid al-Wazir told BBC Arabic the country had tightened security on cargo shipments leaving its airports.
"We emphasise the need to continue sharing intelligence among the parties concerned in the countries concerned, on a continuing, rapid and urgent basis, so that we can ensure maximum security for our airports, our skies and our planes," he said.
A team of US investigators has already been sent to Yemen to help track down those involved in the plot.
Former Secretary of Homeland Security Michael Chertoff told the BBC that help from the West is vital to the Yemeni authorities, whose anti-terror cababilities "may not be up to the job".
Meanwhile, US investigators are re-examining wreckage of a UPS cargo plane that crashed in Dubai in September.
Two crew members died when the jet crashed shortly after take-off. On Sunday, UAE investigators said there was no evidence that the crash was caused by an explosion.