Officials later said a 22-year-old engineering student was also arrested. She is the daughter of the first woman who was taken into custody.
Authorities said the bombs were expertly constructed and unusually sophisticated.
"The information that we have acquired is that it is a woman who sent those two shipments through those shipping agencies," Saleh said.
Officials were checking dozens more packages, in the wake of the suspected Al Qaeda attack.
Authorities on three continents stopped the attacks when they seized the explosives on cargo planes in the United Arab Emirates and England. The explosives were found in the ink cartridge of a computer printer.
The explosive devices were described by police as being made in a professional manner, rigged to be detonated by a cellular phone or a timer.
After investigators completed a preliminary investigation, British Home Secretary Theresa May said Saturday that the bomb found north of London could have exploded.
May said the plane carrying the package from Yemen may have been the target, and if the bomb had detonated, the explosion could have brought down the aircraft.
"But we do not believe that the perpetrators of the attack would have known the location of the device when they planned for it to explode," May said. "At this stage we have no information to indicate another terrorist attack is imminent."
Investigators don't believe any of the suspicious packages were heading for Southern California, but security is tight at the Los Angeles International Airport, especially at cargo areas.
After a frenzied day of searches in Philadelphia, Newark, N.J., and New York City, no explosives were found inside the United States. All new cargo coming from Yemen has been temporarily banned.
Authorities in Yemen are increasing their search, looking through two dozen more packages in the capital, San'a, to see if there are any more explosive devices heading toward the U.S. Yemeni authorities were also questioning cargo companies contracted to work with FedEx and UPS.
The latest attempted attack has increased fears about an Al Qaeda threat against the U.S. and other Western countries, prompting airports across the country to increase their security - particularly in the cargo areas.
Authorities say terrorists from Yemen mailed the explosives intending them to make their way to synagogues in Chicago, where President Barack Obama plans to be this weekend.
While Obama didn't specifically accuse Yemen's Al Qaeda branch, Obama's counterterror chief John Brennan called it the most active Al Qaeda franchise and said anyone associated with the group was a subject of concern.
That would include the radical U.S.-born Muslim cleric Anwar al-Awlaki, who now is hiding in Yemen. He has been linked in the Christmas attack and has inspired other terrorists with his violent message. Also hiding in Yemen is Samir Khan, an American who declared himself a traitor and helps produce Al Qaeda propaganda.
Since the failed Christmas bombing, Yemen has been a focus for U.S. counterterrorism officials. Before that attack, the U.S. regarded Al Qaeda's branch there as primarily a threat in the region, not to the United States.
Several U.S. officials say this attempted attack is possibly linked to the group behind the failed Detroit airliner bombing last Christmas. The same explosive, PETN, was used in that attempted attack as well.
Obama has called the coordinated attacks a "credible terrorist threat."
The Department of Homeland Security released the following statement regarding the incident:
"As a precaution, DHS has taken a number of steps to enhance security. Some of these security measures will be visible while others will not. The public may recognize specific enhancements including heightened cargo screening and additional security at airports. Passengers should continue to expect an unpredictable mix of security layers that include explosives trace detection, advanced imaging technology, canine teams and pat downs, among others. As always, we remind the public to remain vigilant and report suspicious activity to local law enforcement."
Despite the latest scare, airplane passengers say they're not too worried about flying.
"I haven't really noticed a difference with security in the airports, so it hasn't really affected me," said Ron Dushane, a traveler from Beaumont, Texas.
"If it's a threat, it's a threat. I think it's probably an overreaction, but don't fly a plane if you don't like it," said Thomas Comstock, a traveler from Seattle, Wash.
The Transportation Security Administration has stepped up security using a new method for pat downs. TSA Agents will now be able to touch body parts that were once off limits, like a woman's bra or the inner thigh. TSA officials say this new method aims to stay ahead of new and evolving terror threats.
Passengers will only be subjected to these new pat downs if the electronic screening method sends off a suspicious alarm, notifying that they have metal on them.
The Associated Press contributed to this report.