Washington, Oct 31 (IANS) The cargo terror plot discovered in Britain and Dubai has the "hallmarks of Al Qaeda", a top US official has said.

"We know that the perpetrators of this -- and it has the hallmarks of Al Qaeda -- they are constantly trying things to test our system," homeland security secretary Janet Napolitano said Saturday.

According to Xinhua, the failed terror plot, in which two suspicious packages were found Thursday night on cargo planes originated from Yemen and destined for the US, has spurred security scare across the Atlantic.

"What happened is you have great information sharing from the Saudis," Napolitano said in an interview with CNN. "We were immediately able to work across the globe to get these packages segregated."

Napolitano's statement came in line with that of other top US officials who are increasingly confident that Al Qaeda was behind the plot, even though they stressed investigation is still underway and no final conclusion can be drawn at this point.

"We know that Al Qaeda in the Arabian peninsula (AQAP), the terrorist group based in Yemen, continues to plan attacks against our homeland, our citizens, and our friends and allies," US President Barack Obama said Friday.

The AQAP was responsible for the failed terrorist attack on Christmas Day last year, when a Nigerian man tried to bomb a US-bound airliner.

A Yemeni senior security official told Xinhua Friday that initial investigation showed that the AQAP was behind the suspected packages found on the flights from Yemen to the US.

US security officials have indicated that Saudi Arabia has provided critical tip-offs in discovering this potentially disastrous plot.

"The US is grateful to the Kingdom of Saudi Arabia for their assistance in developing information that helped underscore the imminence of the threat emanating from Yemen," John Brennan, assistant to the president for homeland security and counterterrorism, said in a statement Friday.