The Federal Aviation Administration raised concerns over flying in low altitude during landing and take-off, and while the aircraft are parked, due to terrorist activity.
"The Department of State warns US citizens against all non-essential travel to Pakistan," the travel advisory, issued yesterday, said. Consular services provided by the American Embassy in Islamabad, the Consulate General in Karachi, and the Consulate General in Lahore have been curtailed. The Consulate General in Peshawar is not providing consular services, the note said.
"Pakistan continues to experience significant terrorist violence, including sectarian attacks," the US State Department said, adding that targeted attacks against government officials, humanitarian and non-governmental organisation or NGO employees, tribal elders, and law enforcement personnel are common.
"Throughout Pakistan, foreign and indigenous terrorist groups continue to pose a danger to US citizens. Evidence suggests that some victims of terrorist activity have been targeted because they are US citizens. Terrorists and criminal groups have resorted to kidnapping for ransom," the travel advisory said.
If any American citizen chooses to live or travel in Pakistan despite the warning, the person should vary travel routes and timing, especially for routine trips, and minimise duration of trips to markets, restaurants, government and military institutions, the advisory said.
Americans travelling to Pakistan should also minimise the number of US or western nationals congregating in any one location at any time, and avoid hotels that do not apply stringent security measures.
"Take a photo of your passport, entry stamp and Pakistani visa, and keep it with you at all times. Keep digital copies of these documents in a secure, electronically accessible place," the advisory said.
According to the State Department, the Federal Aviation Administration or FAA in an "Advisory Notice to Airmen" issued on December 30, 2016 said that there is a risk to civil aviation operating in Pakistan. The advisory, however, does not prohibit US operators or airmen from operating in the specified area, as it is strictly an advisory notice.
"While there have been no reports of man-portable air defence systems (MANPADS) being used against civil aviation in the territory and airspace of Pakistan, some extremist/militant groups are suspected of having access to MANPADS," the FAA said.
"As a result, there is a potential risk for terrorists to target civil aviation with MANPADS at low altitudes. Some MANPADS may be able to reach a maximum altitude of 25,000 feet," it said.
FAA said that additionally, cross-border tensions in the Kashmir region rose from August to September 2016 due to extremist and terrorist activity, and operators should be alert to the possibility of temporary airspace restrictions issued by the air navigation service providers responsible for managing that airspace.
In June 2014, terrorists attacked Jinnah International Airport in Karachi, killing 30 people and damaging he building. "During several separate incidents in 2014, aircraft on approach into Peshawar's Bacha Khan International Airport were fired on by small arms, which resulted in one fatality," the FAA said.