The youths identified as Sachin and Hemant Malik, both property dealers, were nabbed but later released as nothing suspicious was found with them, police said, adding no one was injured in the firing.

CISF personnel detected the two men sitting on the railway track just outside the exit gate No 14 near the funnel area of the runway at 1:10 a.m. and the youths started running towards their car as security men intercepted them, CISF spokesperson Rohit Katiyar said.

Apprehending trouble at the airport which is on high alert since the November 26 Mumbai terror attacks, the CISF men first fired once in air and subsequently twice on the wheels of their car.

"They started running and to stop them, our personnel fire a shot in the air but they entered their car and tried to drive away. Two shots were fired at the car's tyres," Katiyar said, adding no one was injured in the firing and both were handed over to Palam Village police station.

The two claimed they were consuming alcohol at the time of incident and thought that police had come to catch them, a senior Delhi Police official said.