WASHINGTON - (AP) - Yemeni authorities arrested a woman Saturdayand searched for other suspects linked to al-Qaida's Persian Gulffaction in the plot to mail bombs powerful enough to down a cargoplane.

Officials said the woman was detained as part of a wideningsearch for people believed to have used forged documents and IDcards in the plot thwarted Friday. Authorities on three continentsscrambled to check planes from Philadelphia to central England,recovering two live explosive devices addressed to two synagoguesin Chicago.

The dragnet in Yemen and the results of a preliminaryinvestigation into one of the bombs in Britain reflected theseriousness of a plot that investigators said bore all thehallmarks of al-Qaida. Yemeni officials said the suspects werebelieved linked to al-Qaida in the Arab Peninsula, the group'saffiliate in the Persian Gulf.

Yemen's president, Ali Abdullah Saleh, told reporters that theU.S. and the United Arab Emirates had provided information thathelped identify the woman as a suspect.

Two security officials told The Associated Press the woman wasarrested in the al-Rawdah district near the airport in San'a,Yemen's capital. "According to our information, a woman has sentthe packages through the agents (companies)," Saleh said in hisbriefing.

One of the Yemeni officials, a member of the country'santi-terrorism unit and close to the Yemeni team probing the case,said the other suspects had been tied to al-Qaida's faction inYemen.

Several U.S. officials said they increasingly are confident ofthe involvement of al-Qaida's Yemen branch, the group behind thefailed Detroit airliner bombing last Christmas. A Nigerian-bornpassenger tried to set off a bomb packed with PETN, an industrialexplosive that was the same potent ingredient used in the mailbombs found Friday. But the suspect's underwear detonator failed tooperate properly.

U.S. officials said al-Qaida's explosives expert in Yemen,Ibrahim Hassan al-Asiri, was the likely suspect behind thebombmaking. Al-Asiri helped make the bomb used in the Christmasattack and another PETN device used in a failed suicide attackagainst the top Saudi counterterrorism official last year,officials said.

A U.S. official also said both bombs seized on Friday wereattached to power supplies, a further indication that they wereviable. All the officials spoke on condition of anonymity becauseof the sensitivity of the investigation.

U.S. investigators said the mail bombs found in the UAE andEngland were headed to two synagogues in Chicago. But British HomeSecretary Theresa May said it was possible that the cargo planecarrying the package from Yemen may have been the target, too.

A second package was discovered in Dubai, where white powderexplosives were discovered in the ink cartridge of a printer,police said in a statement. The device was rigged to an electriccircuit, and a mobile phone chip was hidden inside the printer, thestatement said.

The bombs were constructed to be activated by cell phone and atimer, but investigators have not found either of those devices,said Rep. Jane Harman, D-Calif., a member of the House HomelandSecurity Committee who was briefed on the investigation.

Officials continue to investigate whether the bomb would haveworked, a U.S. official said.

Yemeni authorities were checking dozens more packages in thesearch for the terrorists who sent the bombs, though there were nosigns of additional explosives. Authorities questioned cargoworkers at the airport as well as employees of the local shippingcompanies contracted to work with FedEx and UPS, a Yemeni securityofficial said.

The White House said President Barack Obama's counterterrorismadviser, John Brennan, called Yemen's president and made clear thatthe U.S. was ready to help his government against al-Qaida. TheU.S. already assists Yemen with air strikes and othercounterterrorism information.

U.S. officials temporarily banned all cargo shipments fromYemen. An employee at the UPS office in Yemen said the office hadbeen instructed not to receive any packages for delivery for thetime being. The U.S. Postal Service has decided not to accept anyinbound mail from Yemen for now.

The U.S. has FBI, military and intelligence officers stationedin the country to conduct an inquiry. There are only a fewinternational shipping locations in the impoverished Arab nation,but U.S. officials worried that record keeping would be sparse andinvestigators would have to rely more on intelligence sources toidentify the would-be bombers.

Yemen is home to the radical U.S.-born Muslim cleric Anwaral-Awlaki, who's linked to the Christmas attack and has inspiredother terrorists with his violent message. Also hiding in Yemen isSamir Khan, an American who declared himself a traitor and helpsproduce al-Qaida propaganda.

Intelligence officials were onto the suspected plot for days,officials said. The packages in England and Dubai were discoveredafter Saudi Arabian intelligence picked up information related toYemen and passed it on to the U.S., two officials said.

U.S. intelligence officials warned last month that terroristshoped to mail chemical and biological materials as part of anattack on the United States and other Western countries. The alertcame in a Sept. 23 bulletin from the Department of HomelandSecurity that was obtained by The Associated Press.

Since the failed Christmas bombing, Yemen has been a focus forU.S. counterterrorism officials. Before that attack, the U.S.regarded al-Qaida's branch there as primarily a threat in theregion, not to the United States.

The Yemen branch, known as al-Qaida in the Arabian Peninsula,has since become a leading source of terrorist propaganda andrecruiting. Authorities believe about 300 al-Qaida members operatein Yemen.