WASHINGTON — The United States has lifted its ban on US-bound air cargo shipments originating in Yemen, the Transportation Security Administration said Tuesday.

A global security alert was sparked in October by the discovery of explosives in two parcels posted from Yemen.

The two potentially lethal parcels were addressed to synagogues in Chicago and contained the explosive PETN hidden in ink toner cartridges. They were uncovered in Dubai and Britain on October 28.

German officials have said the explosive used was difficult to detect and easy to pack into seemingly innocuous devices. The discovery of the bombs led several countries to ban all air freight originating from Yemen.

“Following the disruption of an attempt last October to ship explosive devices on board aircraft bound for the US, TSA and the Customs and Border Protection (CBP) took immediate measures to enhance existing protocols for screening inbound cargo, including grounding packages originating from Yemen destined for the US and deploying a team of inspectors to assist the government of Yemen with their cargo screening procedures,” the TSA said in a statement.

TSA Administrator John Pistole also visited ahead of tours by several US teams.

“As a result of this partnership, air cargo originating from or traveling through Yemen may proceed to the US,” the TSA explained. “Such cargo must be screened to specified standards prior to departing Yemen, and will receive additional attention as necessary en route to the US, while also being subject to multiple layers of security.”