A man scaled the perimeter wall of the Delhi airport and reached the runway before being apprehended, in a serious security breach during a high alert in the national capital due to the ongoing Republic Day celebrations, official sources said Sunday.

The Central Industrial Security Force (CISF), responsible for securing the "hypersensitive" Indira Gandhi International (IGI) Airport, has suspended a head constable on charges of dereliction of duty.

The intruder, who was found to be intoxicated, was first spotted on the runway by the pilot of an Air India flight around 11:30 pm on Saturday, they said.

The pilot informed the Air Traffic Control (ATC) which directed the CISF to pursue the intruder.

The man hailing from Haryana was apprehended by Central Industrial Security Force (CISF) personnel and handed over to the Delhi Police, they said.

The paramilitary force launched an inquiry into the serious security breach at the "hypersensitive" civil aviation facility and has suspended a head constable who was on duty that day, the sources told PTI.

The "alarming" incident came during the high-alert sounded by security agencies for the ongoing Republic Day celebrations with special measures to check sabotage activities in view of the extreme cold weather and accompanying fog, a senior officer said.

Republic Day celebrations will culminate with the Beating Retreat ceremony on Monday.

The CISF provides a counter-terrorist security cover to the Indira Gandhi International (IGI) Airport and is responsible for securing its perimeter wall too.

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