Former Indian President APJ Abdul Kalam, popularly known as the Father of India's missile program, died in the northeastern state of Meghalaya Monday at the age of 83.

Kalam collapsed during a lecture at a management institute in state capital of Shillong late in the evening. He was rushed to a hospital where doctors declared him brought dead "due to cardiac arrest".

Prior to serving as India's 11th President from 2002 to 2007, Kalam was closely linked to India's civilian space program and military missile development efforts.

He had also played a key role in India's Pokhran-II nuclear tests in 1998, which earned him the title of "India's Missile Man".

Indian President Pranab Mukherjee described Kalam's death as his personal loss. "His warmth, humility and simple ways endeared him to one and all," President Mukherjee said in a message.

"He had a special love for children and sought to constantly inspire the youth of our country through motivational speeches and personal interaction," said the message.

Indian Prime Minister Narendra Modi condoled Kalam's death. " India mourns the loss of a great scientist, a wonderful President and above all an inspiring individual," he said.

Modi added: "My mind is filled with so many memories, so many interactions with him. Always marvelled at his intellect, learnt so much from him."

The Indian government is to declare a national mourning for seven days for the death of Kalam who fought all odds to rise from a poor Muslim family and earn degrees in physics and aerospace engineering.