The Pakistan Navy detected and blocked an Indian submarine from entering Pakistani waters on October 16 (last Saturday), the military's media wing revealed on Tuesday.
The Inter Services Public Relations (ISPR) said the navy showed "unremitting vigilance and professional competence" in ascertaining and blocking the attempted entry of the Indian vessel.
"During the prevailing security milieu, a strict monitoring watch has been kept by Pakistan Navy to safeguard maritime frontiers of Pakistan," the ISPR said.
It added that the Oct 16 incident was the third time an Indian naval submarine had been detected and tracked by the Pakistan Navy's long-range maritime patrol aircraft.
"The recent incident reflects the deplorable Indian machinations vis-à-vis commitment and resolve of Pakistan Navy to defend maritime frontiers of the motherland," the statement reads.
The last such reported incident occurred in March 2019 when the navy had detected and thwarted a similar attempted entry by an Indian submarine. "The Pakistan Navy used its specialised skills to ward off the submarine, successfully keeping it from entering Pakistani waters," a statement from the navy's spokesperson had said at the time.
Another attempt was made in November 2016 when an Indian submarine was tracked and pushed clear out of Pakistan's waters.
The UN Convention on Law of Sea does not allow a state to carry out manoeuvres or exercises in the exclusive economic zone (EEZ) and in the continental shelf of another coastal state without its consent. EEZ signifies an area of coastal water and seabed within a certain distance of a country's coastline that cannot be entered without permission or prior information.
The area of Pakistan's territorial waters is 12 nautical miles while its seabed territory (EEZ) grew to 290,000 square kilometres in 2015.