The US aviation regulator Federal Aviation Administration has issued an advisory to all air carriers and commercial operators against flying into or crossing the Pakistan airspace citing "extremist/militant activity". "There continues to be a risk to US civil aviation from attacks against airports and aircraft, particularly for aircraft on the ground and aircraft operating at low altitudes, including during the arrival and departure phases of the flight," reads the advisory. The US regulator said in its NOTAM that there continues to be a risk to US civil aviation sector from attacks against airports and aircraft in Pakistan, particularly for aircraft on the ground and aircraft operating at low altitudes, including during the arrival and departure phases of flights. "The ongoing presence of extremist/militant elements operating in Pakistan poses a continued risk to US civil aviation from small-arms fire, complex attacks against airports, indirect weapons fire, and anti-aircraft fire, any of which could occur with little or no warning," it said. In justification to the advisory, the FAA also makes mention of the Balakot airstrike by the IAF and the subsequent capturing of Indian Air Force Wing Commander Abhinandan Varthaman by Pakistan in February last year, besides escalating tensions between India and Pakistan over the Kashmir issue. "India and Pakistan employ a variety of advanced air-to-air fighter aircraft and surface-to-air missile systems capable of targeting aircraft up to and beyond overflight altitudes typically used by civil aircraft." The advisory, however, makes note that both India and Pakistan have "no intent to target civil aviation", but warns that "if military operations were to resume, such operations could present an inadvertent risk to the US civil aviation." It has also cited the presence of extremist groups in Pakistan. "Between 2014 and 2019, extremist/militant groups operating in Pakistan have demonstrated their ongoing capability and intent to target civil aviation through multiple attacks on aviation infrastructure, including airports," the advisory reads. The advisory, posted on December 30, 2019, will be reevaluated on January 1, 2021, the notice said. The regulator added that pilots or airlines must report safety or security incidents - which may happen in Pakistan - to the FAA. Pakistan on July 16 last year opened its airspace for India after about five months of restrictions imposed in the wake of a standoff with New Delhi. Following the Balakot airstrikes by the Indian Air Force, Pakistan had closed its airspace on February 26 last year. Pakistan in October last year had also denied India's request to allow Prime Minister Narendra Modi's VVIP flight to use its airspace for his visit to Saudi Arabia over the Kashmir issue.