The Benazir Bhutto International Airport, the Pakistani capital’s largest airport, was put on red alert Monday due to a security threat, news reports indicated. The Islamabad airport was cleared roughly an hour later and resumed normal operations, the Pakistan Civil Aviation Authority posted on Twitter. 

All entrances and exits were shut and flights scheduled to land were diverted to alternate airports after reports of “intruders” at the airport. The emergency came on the same day Pakistani authorities issued eight arrest warrants for militants associated with an attack on the Karachi airport in June that killed at least 37 people, including 10 militants.

Jawad Nazid, 25, who owns the unofficial Twitter account of the Pakistani air traffic authority, told International Business Times via Twitter the “intruders” were “non-state actors” who were “trying to do stuff which is termed ‘illegal.’” One source reported on Twitter two men were held, but there has been no official confirmation by law enforcement officials.

At least one flight, Pakistani International Airlines Flight 853 from Beijing, was diverted to Karachi, the country’s largest airport. Thai Airways Flight 350 took off from Islamabad en route for Bangkok later in the night following an emergency-related delay, the Pakistani Express Tribune reported

Among the arrest warrants issued Monday were those for Pakistani Taliban leader Mullah Fazlullah and Shahidullah Shahid, a former spokesman for the militant organization,  Khaleej Times reported.

Tehreek-e-Taleban Pakistan (TTP), an offshoot of the Taliban that recently pledged its support to the Islamic State group, claimed responsibility for the June attack. The TTP besieged the airport, leading to what was described as an “all-night battle” between Pakistani law enforcement and militants, the Khaleej Times reported.

The Taliban in Pakistan claimed responsibility for last week's horrific attack on the Peshawar Army School that left 148 people, including 132 children, dead.