Pakistani airspace over Multan remained off-limits for two hours on Friday, which sources said was because of an apparent secret military exercise that involved the use of air space over the city, forcing a delay in the flights of two Pakistan International Airlines (PIA) planes. According to sources, two PIA flights, PK-652 and PK-682, were denied entry into Multan’s airspace without explanation or reason citing any reasons. The first plane was bound for Lahore from Hyderabad via Multan, but was forced to land in Sukkur, while the second was heading to Multan from Lahore, but was recalled as soon as it took off. The Pakistan Army, which has been on silent alert since the November 25 NATO attack, was said to be conducting a secret exercise near Multan, and hence wanted to ensure that all land and airspace remained free of traffic. “The planes were ordered down or diverted because of this exercise,” another source said. “This was done to avoid any mishap or disaster.”