India's foreign minister on Sept. 16 lodged a formal protest with Pakistan's charge d'affaires after a Pakistani naval vessel on Sept. 15 collided with an Indian warship in the north Arabian sea in what New Delhi described as an act of "unacceptable and unprofessional conduct," Reuters reported on Sept. 16. Unnamed Indian sources said the Pakistani ship moved toward and eventually collided with an Indian warship conducting a routine surveillance mission, and while consequent damage was purportedly minor, they characterized the incident as violating a 1991 agreement between the countries mandating at least three nautical miles of distance between their naval units to avoid accidents.