By Euan McKirdy and Daniel Silva Fernandez

CNN

(CNN) -- If you're flying from Mexico to the US, be prepared for an extra-long security line.

Starting Wednesday, passengers on direct flights to the US will have to undergo extra security checks for portable electronic devices larger than a phone.

Mexico's civil aviation authority issued the alert in a statement late Tuesday, after they said they were informed by the US Department of Homeland Security (DHS) to implement the extra layer of security.

"Airlines will apply extraordinary measures" beginning on Wednesday, the General Directorate of Civil Aviation of the Ministry of Communications and Transportation said in a statement.

No additional information was given on the reason for the change in security protocol.

Passengers planning to travel into the US are advised that they "must show up at the airport three hours before departure to comply with the procedures."

Devices that passengers take with them into the cabin will be subjected to safety checks and should be presented separately from the rest of the luggage, and without a cover or any other protection.

Laptop ban still in effect

The move echoes recent laptop bans that the DHS has imposed on incoming flights to the US from eight countries in the Middle East and North Africa.

In that case, officials feared the devices could be used to smuggle explosives on board.

CNN Money reported earlier in July that passengers flying to the US from foreign airports still affected by the electronics ban may soon be able to bring their laptops on board the plane.

Earlier this month, US officials lifted the ban for passengers coming from Istanbul, Turkey; Doha, Qatar; Amman, Jordan; Abu Dhabi and Dubai in the United Arab Emirates; and Kuwait after airports and airlines implemented heightened security measures.

Egypt Air said in a statement at the time that restrictions on its flights from Cairo to New York had also been lifted.