They said, Pakistan has also been asked to share results of the investigations with the Indian High Commission.
The sources also noted that the website of the Indian High Commission continues to be intermittently blocked which is causing inconvenience and has affected normal functioning of the Mission.
"Such incidents of harassment, intimidation and threats to physical security of diplomats and officials are in violation of the Vienna Convention on Diplomatic Relations of 1961, and a threat to the security and safety of the personnel of the high commission of India," a source said.
Pakistan has been told that the safety and security of Indian High Commission, its officers, staff members and their families is the responsibility of the government of Pakistan, the source added.
On March 19, two officials of the Indian mission went for shopping to Safa Gold Mall and they were aggressively followed by two persons in a car (Toyota Corolla) in close proximity at various locations, sources said. In another incident, they said, two officials travelling in a high commission vehicle were aggressively followed while going to a super market.
India has so far issued 13 note verbales to Pakistan through its mission in Islamabad protesting against these incidents.
Pakistan has also been accusing India of harassing its diplomats and releasing videos of alleged intimidation of its officials. However, the veracity of these videos could not be ascertained.
Islamabad has also called his High Commissioner to India back home for consultations on the issue.