Afghanistan's intelligence service warned candidates in the 2014 presidential election that mobile phones, computers and cameras given to them as gifts could contain hidden bombs.
More than 20 candidates have registered in the race to succeed President Hamid Karzai, and the April election will pose a major security challenge as fighters try to disrupt the US-backed process.
The National Directorate of Security said it had "intelligence information showing that the enemies of Afghanistan are planning to use new terrorist methods to disrupt the elections".
"Avoid accepting gifts such as mobile phones, computers, cameras and other packages before they are checked by your security personnel," it advised.
The Taliban last week claimed responsiblity for a bomb hidden in a microphone that killed the governor of Logar province as he made a speech at a mosque after Eid prayers.
Last year directorate chief Asadullah Khalid was badly injured by a suicide bomber who hid explosives in his underwear.
Senior politician Burhanuddin Rabbani was assassinated by a bomber with explosives in his turban in 2011, while anti-Taliban commander Ahmed Shah Massoud was killed in 2001 by explosives inside a video camera.