The Yemen-based faction Al-Qaida in the Arabian Peninsula (AQAP) has claimed responsibility for a sophisticated plot against the United States in which two expertly-concealed bombs were shipped via the United Postal Service (UPS) and FedEX to the addresses of two Chicago synagogues in late October.

Although the packages were intercepted and the plot foiled, the attempt signifies growing capabilities of terrorist organizations to strike on American soil, and could produce unwanted complications for the air-line shipping industry.

The bombs were concealed inside the ink cartridges of two Hewlett-Packard printers. Using the explosive PETN, which is common to heavy construction, the devices were created to mimic the appearance of normal printer ink and wiring, reports The New York Times.

“The wiring of the devices indicates that this was done by professionals. It was set up so that if you scan it, all the printer components would look right,” said one investigation official to The New York Times, under the condition of anonymity.

A drastic improvement from his previous work, the bombs are believed to be the work of AQAP’s top bomb maker Ibrahim Hassan al-Asiri. Asiri’s previous work includes two failed attempts in 2009, one of which was on a trans-Atlantic flight to Detroit last December, reported The New York Times.

The Washington Post illustrated the increased efficiency and innovation of Asiri’s bombs by comparing his previous airline plot with this recent attempt. Where the first bombing involved 80 grams of PETN stuffed into a bomber’s underwear, these complex computer-part bombs featured 300-400 grams of the explosive, said a German security official who wished to remain unidentified.

Asiri’s other high-profile 2009 attempt was a failed assassination of Saudi Arabian intelligence chief Mohammed bin Nayef, reports The New York Times.

It was a tip from Nayef that alerted international authorities to the plot and lead to the parcels’ interception in Dubai and at Britain’s East Midlands airports, according to The New York Times.

Though not often a reliable ally to the United States, Saudi Arabian authorities have cited the Yemen faction as their largest security threat, according to The New York Times.

With only a single suspect arrested — an unidentified woman who was released when it was discovered her identity had been stolen and used to ship the packages — Yemeni officials have struggled in their at-tempts to suppress the AQAP, reports The Washington Post.

Behind the group’s recent strengthening is the American-born cleric Anwar al-Awaki. According to BBC, Awaki’s YouTube sermons led top King’s College student, Roshonara Choudhry, to attempt a stabbing assassination of British Parliamentary Member Stephen Timms in May.

Awaki’s actions have earned him much attention from the international counter-terrorism community.

With personnel from the FBI, Pentagon, and CIA stationed in Yemen, the United States has had mixed results with a bombing campaign aimed at AQAP’s approximately 300 members hidden throughout an area of desert twice the size of Wyoming, reports The Washington Post.

The system of Saudi Arabian surveillance and spies that first detected the plot, however, is part of a larger international counter-terrorism network that includes the five countries involved in the package’s interception, according to The New York Times.

“It reinforces the need for Western democracies to share information and resources,” said Assistant Professor of Political Science Robert Duncan, who worked for the CIA for nearly 26 years before coming to Guilford.

The successful foil of the plot followed a two-day chase of the parcels and a combined effort by officials in the United States, Britain, Germany, the United Arab Emirates, and Yemen, according to the Associated Press.

Despite successful cooperation between international counter-terrorism authorities, the plot’s near success has raised questions about American vulnerabilities.

Information recently emerged that U.S. intelligence officials intercepted multiple packages containing books, papers and CD’s that were shipped from Yemen to Chicago addresses in September. Though the parcels contained no explosives and were allowed to be delivered, it is believed that these may have been test runs for the organization to better plan timing and logistics, reports The Sydney Morning Herald.

“At the time, people obviously took notice and — knowing of the terrorist group’s interest in aviation — considered the possibility that AQAP might be exploring the logistics of the cargo system,” said an unnamed official to The Washington Post. “When we learned of last week’s serious threat, we recalled the incident and factored it in to our government’s very prompt response.”

While customers have the ability to track packages from the shipper’s website, U.S. Customs authorities gain knowledge about the contents of U.S.-bound cargo planes only four hours before they are scheduled to arrive, according to USA Today.

With over a third of all global trade conducted by air cargo, as reported by Reuters, fears of reactionary measures inhibiting the industry have risen.

“Security cannot bring business to a standstill,” said Administrator for the U.S. Transportation Security Administration John Pistole to Reuters at an aviation security conference. “We must strike a balance (be-tween security and business). The U.S. government understands this well.”

These effects have been seen already.

In the days following the plot, U.S. fighter jets escorted a cargo plane from the Canadian border to New York’s Kennedy International Airport to be searched. Since, both cargo and passenger flights have been banned by multiple European countries, including Britain and Germany, according to The Washington Post.