The sound turned out to be Pakistani Air Force (PAF) F-16 fighter jets, flying over the capital city.
According to the Asia Times, citizens thought they were in the midst of a strike from New Delhi, in retaliation for 18 Indian soldiers killed by armed militants on Monday at the Uri military base in Kashmir. It was the worst attack in over 20 years and intensified long term tensions between the two countries.
Rajnath Singh, India’s Home Affairs Minister tweeted, "Pakistan is a terrorist state and it should be identified and isolated as such."
Khawaja Asif, the Defense Minister of Pakistan, tweeted several images of the country’s aircraft taking off from motorways. He wrote, "The defenders of our skies, in a state of constant readiness, Alhamdolillah (Praise be to God). Our motorways are our runways."
Commodore Javed Mohammad Ali, a PAF spokesman, clarified that the launch was part of a routine two-day drill called High Mark, claiming that the exercise prepares pilots to deal with damaged runways.
Indian diplomats at the UN General Assembly on Thursday called Pakistan a "terrorist state" that’s "guilty of "war crimes," including harboring and training terrorists. Eenam Gambhir, First Secretary in the Permanent Mission of India to the UN said, "When practised as an instrument of state policy, it is a war crime. What my country and our other neighbors are facing today is Pakistan’s long-standing policy of sponsoring terrorism, the consequences of which have spread well beyond our region."
Gambhir claimed that many groups and individuals designated as terrorists by the UN, including Zaki-ur-Rehman Lakhvi, a chief organizer of the 2008 Mumbai attack, and Masood Azhar, who leads the Daesh-supported Jaish-e-Mohammed (JeM), move inside Pakistan with impunity.
Her comments were in response to remarks made by Pakistani Prime Minister Nawaz Sharif at the UNGA, referencing "Indian brutalities" against Kashmiri forces fighting Indian occupation.
A transcription of Sharif’s speech, published on Huffington Post India, reads: "This indigenous uprising of the Kashmiris has been met, as usual, with brutal repression by India's occupation force of over half a million soldiers. Over a hundred Kashmiris have been killed, hundreds, including children and infants, blinded by shotgun pellets and over six thousand unarmed civilians injured over the past two months."
Gambhir said that, instead of making "hypocritical sermons," Islamabad should remember that the Uri attack "is part of a trail of continuous flow of terrorists trained and armed by [Pakistan] and tasked to carry out terrorist attacks in [India]."
India has been strengthening its air warfare capabilities. The country recently inked an €8.7 billion ($9.8 billion) contract with France for the delivery of 36 French-made Rafale fighter jets.