A grenade inside a well of Delhi's iconic Red Fort sparked security concerns before it was removed safely on Friday morning, police said.

The bomb was discovered by some labourers on Thursday evening while they were cleaning the Sawan Bhado garden of the Mughal-era monument, protected by the Central Industrial Security Force (CISF).

"An information about the grenade in the Red Fort well was received on Thursday evening," Deputy Commissioner of Police Jatin Narwal told media. 

"A team of Bomb Disposal Squad and the National Security Guard (NSG) has safely removed it now (Friday morning). The Red Fort has been opened for the public," the officer added.

In February, the police discovered explosives from another well of the same fort complex during a clean up drive.

The Red Fort is one of the heavily secured monuments of Delhi after it was attacked by the Lashkar-e-Taiba in December 2000. The attack left two soldiers and a civilian dead.