"The United States 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," said John Brennan, Assistant to the President for Homeland Security and Counter-Terrorism.
"Their assistance, along with the hard work of the US counter-terrorism community, the United Kingdom, the UAE, and other friends and partners helped make it possible to increase our vigilance and identify the suspicious packages in Dubai and East Midlands Airport," Brennan said.
Earlier, at a hurriedly convened news conference, Brennan said the US is working very closely with its partners in Yemen, United Arab Emirates, the United Kingdom and other countries.
"We know that al Qaeda in the Arabian Peninsula has been trying to carry out attacks against US and Western interests, as well as against Yemenis. So as we continue with this investigation, we are trying to understand who is behind it, the responsibility, and make sure that we understand the scope of the threat that we might face," Brennan said.
The White House official the federal authorities have identified two packages right now. "They have been isolated and they have been made inert. So, therefore, what we’re trying to do now is to make sure that we are able to address any other threats that might be out there," he said.
Both of these packages that have been identified to date originated in Yemen. "So I think it is very prudent for us to make sure that other packages that might be coming in similar routes or from Yemen, as well, are looked at very carefully. And that's what we’re doing right now. But there are only two packages right now that have materials of concern," he said.
Brennan, who was the first one to inform US President Bareck Obama about it, said it does appear that there were explosive materials in both of these packages, that they were in a form that was designed to carry out some type of attack.
"The forensic analysis is underway. We are relying heavily and working closely with our partners in this regard. But clearly, from the initial observations, the initial analysis that's done, that the materials that were found and the device that was uncovered was intended to do harm," he said.
"What we are doing is looking at all individuals that we think might be involved in this. Al Qaeda in the Arabian Peninsula has been rather open in its venom towards the United States, towards Western interests. There are a number of individuals there that we're very concerned about, so we're looking at all possibilities," he said.
"I think over the years al Qaeda has demonstrated that it has focused intently on the aviation sector. A lot of its plots have focused on trying to carry out attacks against aircraft, using aircraft also as potential missiles, as we well know," Brennan said.
"So the aviation industry has taken those steps over the years expressly because al Qaeda -- and when I'm talking about al Qaeda I'm not just talking about al Qaeda in the FATA area in Afghanistan.
"I'm talking about the franchises, including in Yemen, which have demonstrated very clearly that not only are they intending to do certain things against this homeland, but that, as we saw last Christmas Day with Umar Farouk Abdulmutallab, that they will, in fact, take steps to carry out those intentions," Brennan told reporters.
He said the US has been concerned about passenger aircraft and cargo planes, commercial airliners, others, for many, many years. At this point of time, he said the US is looking at all possibilities at this point.
"We don't want to presume that we know the bounds of this plot, so we are looking at all types of packages, air travel, whatever. We just want to make sure that we are going to whatever length we need to, to ensure the safety and security of air travel at this point," he said.
Given that these packages originated from Yemen, Brennan said the US has taken some steps to ensure that packages that come from Yemen are going to be carefully screened.
"We're working with the Yemeni government right now," he said.
"So at this point, one of the reasons why we looked at some planes that were coming down into Philadelphia and Newark today is because they were, in fact, carrying cargo from Yemen.
So we have had these inter-agency meetings to discuss all these options. I don't want to go into the details of this because this is all part of the security measures that are in place, but several of these measures have already been instituted."
Brennan said the decision to send fighter jets to escort that Emirates flight into New York today was made by US military and Canadian military air force. "If there's a threat -- and my understanding -- and I've only seen some of the preliminary reports about this -- is that there was concern about possible cargo on that flight. And so, again, with an abundance of caution, sometimes our air force, the Canadian air force -- will scramble some jets to make sure that everything is okay," he noted.