Police acting on a tip discovered a powerful bomb planted on a bicycle in a busy shopping district in the Sri Lankan capital on Tuesday, an official said.

The explosive was concealed among cabbages and other vegetables in a box on the back of a bike in the eastern Colombo neighborhood of Berolla, Police Chief Inspector Percy Perera told The Associated Press.

CountryWatch: Sri Lanka

Police and army cordoned off the area and people were evacuated from nearby homes, shops and offices while the bomb squad defused the explosive.

He said a remote control was found on the other side of the street, which is usually packed with street vendors, shoppers and commuter buses.

The officer who found the device, Constable Ranasinghe, told The Associated Press at the scene that a grocery store owner noticed the abandoned bicycle and alerted police. The constable declined to give his first name.

Government spokesman Keheliya Rambukwella said the device was about 8 kilograms (17 pounds). He declined to provide any further details about the nature of the device or who might have been responsible for planting it.

"An investigation is still on going and we cannot yet come to any conclusion," he said.

The Media Center for National Security said a high-profile official may have been the target.

Early last week, an auto rickshaw packed with explosives detonated on a busy road near a convoy carrying Pakistan's high commissioner, Basir Ali Mohmand.

The diplomat escaped the Aug. 14 blast unhurt, but at least seven people were killed, including four army commandos guarding the envoy.

Suspicion for that explosion has fallen on separatist Tamil Tiger rebels who have frequently used improvised explosives to target security forces and officials during their more than two-decade battle for a separate homeland for the country's ethnic Tamils.

Security has been tightened in Colombo over the last few days as rumors of explosive-laden vehicles driving around the capital have put the city on edge. Police on Monday started checking all cars, trucks and buses coming into the capital.

Underscoring the tense security situation, bomb disposal experts were called out to investigate a second suspected bomb threat in the capital on Tuesday, which turned out to be a hoax, an investigating police officer said.

A parcel labeled as a "time bomb" found by the driver of an auto rickshaw in his three-wheeled vehicle, was in fact, a tube of hair gel, the officer, who declined to give his name, said.