A drone was spotted over the Indian High Commission complex in Islamabad late last week, prompting India to lodge a strong protest with Pakistan over the incident, people familiar with the development said on Friday.

They said India considered the incident as a breach of security that triggered concerns in the mission.

The Indian mission has already taken up the issue strongly with the Pakistani authorities through a note verbale.

There was no official comment on the incident yet that came to light amid growing concerns in the security establishment in India after explosives-laden drones were used to carry out an attack on the Jammu Air Force station on June 27.

According to security officials, it was the first instance of suspected Pakistan-based terrorists deploying unmanned aerial vehicles to strike at vital installations in India.

Army Chief Gen MM Naravane on Thursday said that the easy availability of drones has increased the complexity of security challenges from both state and state-sponsored actors.

A day after the attack on the Air Force station attempts to target the Ratnuchak-Kaluchak military station in Jammu with drones was thwarted by soldiers.