Sri Lanka has temporarily banned the use of unmanned aircraft and drones following Easter Sunday bombings.
The country's Civil Aviation Authority (CAA) said it was taking the measure "in view of the existing security situation in the country".
Meanwhile, police forces continued to comb the Sri Lankan capital for possible clues to the attacks. Officers set off more controlled detonations of suspicious items, and stopped and searched vehicles.
So far, 76 people have been arrested with suspected terror links.
The father of two of the suspected bombers was detained on Thursday, with his house thoroughly inspected by officers.

Landslide at Guinea landfill kills 30, government says
New Zealand to introduce bill banning social media for children under 16
Drone attack kills 2 children, burns logistics hub in Russia's Krasnodar
Offices, schools closed in southern Taiwan due to torrential rain
Israeli airstrikes in Gaza kill 2 people, injure 7