Pakistan on Saturday (7) said it had denied India's president Ram Nath Kovind permission to fly through its airspace -- access to which is usually granted -- due to New Delhi's recent "behaviour".
The decision comes at a time of high tension between the two nuclear-armed South Asian neighbours over the disputed Himalayan region of Kashmir.
"The decision has been taken in view of India's behaviour," Pakistani foreign minister Shah Mehmood Qureshi said in a statement.
"The Indian president had sought permission to use Pakistan's airspace to travel to Iceland, but we decided not to permit him," Qureshi added, without giving further details.
Indian government spokesman Raveesh Kumar said New Delhi regretted the decision, and that flight clearance to a "VVIP" is "otherwise granted routinely by any normal country".
"We call upon Pakistan to recognise the futility of such unilateral actions," Kumar said.
Pakistan had closed its airspace to Indian traffic in February after a suicide bomb attack that killed dozens of Indian troops in Kashmir, ratcheted up tensions between the two neighbours and prompted aerial dogfights.
It reopened its skies for all civilian traffic in July, ending months of restrictions that had affected major international routes.
Saturday's decision came a day after Pakistan marked Defence Day, which commemorates a brief 1965 war with India over Kashmir.
"Pakistan firmly stands with Kashmiris for their right to self-determination," Prime Minister Imran Khan said Friday during a visit to military posts and families of fallen soldiers in Pakistan's portion of the territory.
India stripped the Himalayan region of its seven-decade-long semi-autonomous status through a controversial presidential decree in August, just hours after it imposed a crippling curfew on the picturesque valley.
Islamabad responded by downgrading its diplomatic ties with New Delhi in August, expelling the Indian envoy, suspending trade and calling back its ambassador in a deepening row over New Delhi's clampdown in its portion of Kashmir.
New Delhi has long maintained that the Kashmir issue can only be resolved bilaterally with Pakistan.
But Islamabad called for the international community to intervene and vowed to take the matter to the United Nations Security Council.
During a meeting with Khan in July, US president Trump said that Indian prime minister Narendra Modi had asked him to help mediate the Kashmir dispute. India has strenuously denied the claim.
An armed rebellion against New Delhi's rule has raged in the Indian-administered portion of the territory since 1989, claiming more than 70,000 lives -- mostly civilians.
