The United Nations' aviation agency has asked Pakistan for more information about an overflight request from India, it said on Tuesday, after Islamabad denied permission to Prime Minister Narendra Modi to cross its airspace on an overseas tour. Tension has flared between the neighbors over the disputed Kashmir after India stripped the Himalayan region of its autonomy and severed telecoms links for months, with flights over Pakistan becoming the latest sticking-point in relations. Modi, who flew to Saudi Arabia on Monday for an investors' summit, took a circuitous route because of Pakistan's refusal, an Indian foreign ministry source said. India had taken up the issue with the International Civil Aviation Organisation (ICAO), the official added. "It is a standard thing we do, we seek permission from the countries on the route," said the official, who sought anonymity because of the sensitive diplomatic situation. "It was done in this case too, and it was refused." Pakistan's Foreign Minister Shah Mehmood Qureshi said Modi was being blocked because of his government's repression in the Muslim-majority territory of Kashmir. "In the context of the gross Indian atrocities in occupied Kashmir, we have decided not to allow him use our airspace," he said in a ministry statement on Sunday. India withdrew Kashmir's special status in August in order to tighten its grip over the region and clamped down on public gatherings, telecommunications and detained scores of leaders, provoking condemnation from Pakistan. Islamabad previously refused a request in September from Modi to cross its airspace on a flight to Germany as tension runs high over Kashmir. In Montreal, ICAO spokesman Anthony Philbin said India had sent the agency a letter about Pakistan's refusal to grant overflight clearance. It is not clear, however, what action the agency could take to resolve the dispute between Islamabad and New Delhi over such clearance. The 1944 Convention on International Civil Aviation, which established ICAO and promotes cooperation between countries, only applies to the operations of civilian aircraft, and not to state or military aircraft. Philbin said he believed flights carrying national leaders were considered state aircraft, and so not subject to ICAO provisions. A similar ratcheting-up of tension led to an aerial clash between the arch foes in the skies over Kashmir this year, prompting Pakistan to shut its airspace for months to all aircraft traveling to and from India, forcing airlines to take longer routes. — Reuters