Kenya's Ministry of Foreign Affairs and International Trade published an advisory on Saturday, cautioning its citizens to avoid travel through Heathrow. The warning, the ministry said, was sourced to "information provided by U.S. officials."
"According to information provided by U.S. officials, al-Qaeda operatives in Yemen and Syria were developing sophisticated bombs that could bring down a plane. The information states that Britain would be the most likely country to be affected.
"Based on this information, Kenyans are advised NOT to travel through London Heathrow where there is substantial threat of a possible attack. Kenyans are therefore advised to seek alternative travel routes to connect to the United States and European countries. These include Doha, Abu Dhabi, Dubai, Amsterdam and Addis Ababa in order to minimize the risk and avoid possible delays."
The warning appears to be related to an announcement from U.S. Department of Homeland Security Secretary Jeh Johnson on July 2 that U.S. officials had decided to enhance security "at certain overseas airports with direct flights to the United States."
At the time of the DHS announcement, a homeland security official told CNN that the focus would be on airports in Europe and the Middle East, and that the increased security protocols were being taken in response to new intelligence that suggested terror groups were working to create improvised explosive devices that would be more difficult to detect.
In the July 2 notice, Johnson acknowledged that "We are sharing recent and relevant information with our foreign allies ... These communications are an important part of our commitment to providing our security partners with situational awareness about the current environment and protecting the traveling public."