Security forces were out in force in the Yemeni capital Sanaa Security forces in Yemen have arrested a female medical student suspected of posting bombs found on two cargo jets in Dubai and the UK.
She was held at a house in the capital, Sanaa, after being traced through a phone number left with a cargo company.
Earlier, UK PM David Cameron said the device found in Britain on a US-bound cargo plane had been designed to go off on the aircraft.
The two packages were addressed to synagogues in the Chicago area.
Both bombs, discovered on Friday, were apparently inserted in printer cartridges.
Germany announced it would no longer accept air freight from Yemen, Agence France-Presse news agency quoted the country's interior minister as saying.
The unnamed young Yemeni woman, described as a medical student and the daughter of a petroleum engineer, was arrested at a house on the outskirts of Sanaa, a security official told AFP news agency.
Her mother was also detained but was not a prime suspect, the arrested woman's lawyer said.
Analysis
AQAP is known to have been developing advanced and inventive bomb-making techniques.
It came close to killing the Saudi interior minister with one device and to bringing down an airliner on Christmas Day with another.
The exact way in which these devices were to be detonated is not clear. This is another sign of growing creativeness allied to ongoing ambition.
Attacking cargo planes has also long been anticipated as a potential tactic. Militant groups regularly look for any weak spots in security and aviation remains a prime target.
Creativeness and ambitionThe lawyer, Abdel Rahman Burman, confirmed to Reuters news agency the student had been arrested on suspicion of involvement in sending the two packages.
"Her acquaintances tell me that she is a quiet student and there was no knowledge of her having involvement in any religious or political groups," he said.
"I'm concerned the girl is a victim because it doesn't make sense that the person who would do this kind of operation would leave a picture of their ID and their phone number."
Yemeni President Ali Abdullah Saleh said the US and the United Arab Emirates had provided Yemen with information that helped identify the woman, and he pledged that his country would continue fighting al-Qaeda "in co-operation with its partners".
"But we do not want anyone to interfere in Yemeni affairs by hunting down al-Qaeda," he added.
Further investigations in Yemen are likely to focus on al-Qaeda in the Arabian Peninsula (AQAP), which has its stronghold in the remote Shabwa province in the south of the country, the BBC's Jon Leyne reports from Cairo.
Pentaerythritol tetranitrate (PETN) - an explosive favoured by AQAP - was discovered in the device intercepted in Dubai.
Mr Saleh's remarks on interference are presumably a message to Washington to hold off military strikes inside Yemen, our correspondent says.
But he says Washington has been impressed by the speed and determination the Yemeni authorities have shown in their response.
Our correspondent says this latest attempted bomb attack will only underscore fears about the security threat from Yemen, where al-Qaeda is taking advantage of weak government, wild geography and huge political social and economic problems that have no clear solutions.
The Yemeni authorities have closed down the local offices of the US cargo firms UPS and FedEx, who have already suspended all shipments out of the country and pledged full co-operation with investigators.
David Cameron: "We believe the device was designed to go off on the aeroplane"
One device was intercepted on a UPS plane at East Midlands Airport in the UK and the other on a FedEx jet in Dubai.
Mr Cameron said the authorities had immediately banned packages coming to or through the UK from Yemen, and was considering further steps.
Late on Saturday, AFP quoted German Interior Minister Thomas de Maiziere as giving an assurance that "no freight coming from Yemen will arrive in Germany".
While details of the device found in Britain have not been released, Dubai police said the bomb intercepted there had been "prepared in a professional manner and equipped with an electrical circuit linked to a mobile telephone [Sim] card".
Rafi Ron, an aviation security adviser to the US government, told the BBC that cargo planes were currently subject to a lot less scrutiny than passenger planes but that this was now likely to change.
"I think that there will be a larger demand for details on the shippers of any item, there will be greater investigation and data mining programmes will be put in place to identify high-risk packages or letters that are put on board, and there will be more technology put in place to screen those packages that will be found serious enough to be screened," he said.
How the alerts were raised (all times GMT):
• Early hours of Friday morning: alert raised at East Midlands airport after suspect package found on UPS plane. Security cordon put in place, then lifted.
• 0900: suspect package found on FedEx plane in Dubai.
• 1300: security cordon reinstated at East Midlands airport, apparently after a second suspect device is found.
• 1700: FBI says two suspect packages were addressed to religious buildings in Chicago.
• 1835: Emirates Flight 201 from Yemen via Dubai lands at JFK airport, New York, escorted by US fighter jets. The plane is carrying a package from Yemen.
• 1845: FedEx in Dubai confirms it has confiscated a suspect package sent from Yemen and is suspending all shipments from Dubai.
• 1900: two other FedEx flights investigated after landing at Newark, New Jersey, and Philadelphia. Both receive the all-clear.
• 2330: BA flight from London to New York (JFK) met by US officials as a "precautionary measure".
This article is from the BBC News website. � British Broadcasting Corporation, The BBC is not responsible for the content of external internet sites.
Source: http://www.bbc.co.uk/go/rss/int/news/-/news/world-us-canada-11660005
Landon Ramm
Alana Handschumaker
Nathanial Maccord
Kristeen Tannery
The British Airline Pilots Association said it had been warning of the risks to cargo flights for years 
