According to a report by CNN, terrorist organizations such as ISIS have developed new ways to hide bombs in electronic devices that, according to the FBI, can go undetected by airport security screenings.

US intelligence agencies are becoming increasingly worried that terrorists have obtained access to airport security equipment, allowing them to test the most effective ways to conceal explosives in electronics, according to CNN. The intelligence reportedly played a large role in the Trump administration’s decision to prevent travelers arriving into the US from eight countries in the Middle East and Africa from bringing laptops and other electronic devices aboard their plane.

However, new information has made some question whether or not the electronics ban is broad enough. CNN states that through multiple tests last year, the FBI determined that new explosives hidden within laptops would be much harder for airport security to detect compared to previous explosives created by terrorists.

“As a matter of policy, we do not publicly discuss specific intelligence information. However, evaluated intelligence indicates that terrorist groups continue to target commercial aviation, to include smuggling explosive devices in electronics,” said the Department of Homeland Security in a statement to CNN. “The U.S. government continually re-assesses existing intelligence and collects new intelligence. This allows DHS and TSA to constantly evaluate our aviation security processes and policies and make enhancements when they are deemed necessary to keep passengers safe. As always, all air travelers are subject to a robust security system that employs multiple layers of security, both seen and unseen.”

Although the newer explosives are harder to detect, US authorities have stated that they are confident that their security screeners and detection machines at airports in the US and Europe are working efficiently and are mitigating any risks through the use of advanced technology and rigorous training.

Aviation security expert Robert Liscouski, a former Homeland Security assistant secretary for infrastructure protection, said that the Trump administration’s decision to limit the electronics ban to eight countries makes sense. “We don’t have the same level of confidence in other areas of the world because we don’t have the government bodies and stature to assure compliance,” said Liscouski, president of Secure Point Technologies.

Initially, US officials were worried that terrorists had developed new methods to hide explosives within battery compartments. However, new intelligence reportedly shows that terrorists have learned how to hide the explosives within devices while ensuring they will operate as normal, long enough for them to get the device past security.

The airline restriction on electronics from eight countries was put into effect on March 21st and bans passengers from taking larger electronic devices onboard planes, forcing them to put them witineir checked luggage. Intelligence officials have stated that it is more difficult for terrorists to detonate a bomb remotely than it is physically. The United Kingdom instituted a similar rule for flights from six countries, including two that were not on the US list.