Four Delhi hospitals received bomb threats on email on Tuesday, two days after similar messages were sent to 20 hospitals, the airport and the office of the Northern Railways' CPRO in the capital, officials said. Nothing suspicious has been found so far. Delhi Fire Service officials said they had received calls of bomb threat emails from the GTB Hospital, Dada Dev Hospital, Hedgewar Hospital, and Deep Chandra Bandhu Hospital in various parts of the city. The bomb disposal squad, bomb detection team, fire department and local police rushed to the spot to conduct searches, the officials said.

According to a DFS official, the spate of calls began at 10.45 am.

The first hospital to call was Deep Chand Bandhu Hospital in north Delhi's Ashok Vihar at 9.45 am. The second call came at 10.55 am from Dada Dev Hospital in Dabri in southwest Delhi, the third at 11.01 am from Hedgewar Hospital in east Delhi's Farsh Bazar and the fourth at 11.12 am from GTB Hospital in Shahdara, also in east Delhi.

"Police and the bomb disposal squad are conducting the checks. We have also conducted checks twice. Nothing suspicious has been found so far," said V K Sharma, security officer at Hedgewar Hospital.

The mail about an explosive in the hospital was received by a doctor at the hospital, he said.

This is the fourth time in the last one month that various places, including schools, have received such threats.

Before Sunday, when the airport and the 20 hospitals got bomb threats, Delhi's Chacha Nehru Hospital received a bomb threat on April 30. On May 1, about 150 schools had got email threats generated from a Russia based mailing service company.

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