New Delhi, Jul 14 (IANS): Security in all Delhi Metro stations was intensified Thursday following the triple blasts in Mumbai that left 17 dead and 131 injured, said an official from the Central Industrial Security Force (CISF).

The CISF, which gives security cover to Delhi Metro, stepped up frisking of passengers and security checks at all its stations.

"The security has been beefed up at all the metro stations in the capital. We cannot give more details on the arrangements that are a part of our policy," CISF's Rohit Katiyar told IANS.

Spanning 183 km and covering 135 stations, the Delhi Metro Rail Corporation (DMRC) runs around 2,000 train trips and ferries more than 16 lakh passengers every day.

"Officials are taking long to frisk male passengers. I have been waiting for 20 minutes, but this is not a time to complain," said Vimal Kalra, a commuter at Pratap Nagar metro station in north Delhi.

"People should cooperate in every way possible."

"We need to check contents such as mobile chargers, liquids, umbrellas. It's a part of the drill," said a CISF official at Patel Chowk in central Delhi.

The national capital was placed on high alert late Wednesday after three blasts rocked Mumbai. One took place at Dadar and the others at Zaveri Bazar and Opera House.