Governments, airlines and aviation authorities around the world are reviewing security after two mail bombs sent from Yemen were intercepted on planes in Dubai and Britain on Friday.

Yemeni police arrested the woman, believed to be in her 20s, after tracing her through a telephone number she had left with a cargo company. The student and her mother were the first people to be arrested in connection with the foiled bomb plot.

Dozens of students staged a sit-in in the courtyard of Sanaa University's engineering faculty calling for her release. "I don't think anyone would carry out a major operation like this and leave behind their real contact details ... I think she's the victim of a conspiracy," student Muhammad Al-Bazili said.

A US official said a Saudi bombmaker believed to be working with Al-Qaeda's Yemen-based wing is a key suspect. Ibrahim Hassan Al-Asiri, who figures on a Saudi list of wanted terrorists, is the brother of a suicide bomber killed in a bid last year to assassinate Assistant Minister of Interior for Security Affairs Prince Mohammed bin Naif.

That attack, as well as another attempt on a US-bound airliner on Christmas Day 2009, involved the use of pentaerythritol trinitrate (PETN) — a highly potent explosive that appears to be the weapon of choice of Al-Qaeda's Yemeni branch, Al-Qaeda in the Arabian Peninsula.

At least one of the two US-bound devices sent from Yemen employed PETN, the US official said.

A Qatar Airways spokesman said that one of the bombs mailed from Yemen traveled on two passenger flights within the Middle East. He said the package containing explosives hidden in a printer cartridge arrived in Qatar Airways' hub in Doha on one of the carrier's flights from Yemen. It was then shipped on a separate Qatar Airways plane to Dubai in the United Arab Emirates, where it was discovered by authorities late Thursday or early Friday.

The German government said Sunday that Germany, Britain, France and the United States had stopped all air freight from Yemen after the discovery of the bombs. Germany's federal crime office (BKA) said it had tipped off British authorities about the parcel bomb intercepted in Britain after it had transshipped through Cologne-Bonn airport. By the time German authorities had been informed about the suspect device, it was too late for them to intervene.

"It was already on the way to Britain," a BKA spokeswoman said. "We managed to inform our partners in London so that they were able to look specifically for the package and find it."