A plane carrying Pakistan’s parliament speaker and a number of politicians was forced to turn around on Thursday, after explosives were found in the airport in Afghanistan where the aircraft was set to land.

According to local media, the plane was about to descend when the pilot turned around from landing at Kabul after explosives, apparently years old, were found near an airport building.

While it was not immediately clear who the explosives belonged to, General Reyaz Arian, the commander of Kabul’s international airport, said the explosives were placed at the airport some years ago during construction work.

As a result of the shock discovery, the airport was shut down for several hours on Thursday and all flights in and out of the Afghan capital were either delayed or turned around.

The flight carrying Pakistan’s parliament speaker will be rescheduled rather than cancelled.

Mohammad Sadiq, Pakistan’s special representative for Afghanistan, tweeted about what he said was a “security threat” to the Pakistani delegation.

“The plane was about to descend when the control tower informed the pilot about the airport’s closure,” he said. “New dates for the visit will be decided after mutual consultations.”

It is understood the Pakistani delegation was to stay in the Afghan capital for three days under the leadership of Asad Qaiser, speaker of the lower house of parliament.