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.

Iran denies talks with US after Trump postpones strikes on power grid
Ukraine's Zelenskyy says Russia preparing new massive attack
Rockets launched from Iraq’s Mosul towards US base in Syria
One killed, 77 hospitalised after Colombian military plane crashes
Hong Kong police given new powers to obtain phone, computer passwords
ICE agents begin deploying at some US airports
Air Canada jet collision shuts LaGuardia; pilots killed, dozens injured
Kuwait launches probe into espionage, state security cases
