New Delhi: Several Delhi schools received bomb-threat emails on Friday, making it the sixth such incident in the last 11 days, officials said.

Security personnel conducted search operations at the schools, but nothing suspicious was found, an official said.

"We received a call regarding the bomb threat at 5:02 am from DPS, Dwarka, in Sector 23," the Delhi Fire Services (DFS) official said on Friday.

Police, the fire department, bomb detection teams, and the dog squad participated in the search operation, but nothing was found so far, another official said.

Around five schools in Dwarka, along with some in other districts, received similar emails, the official said.

At some places, students were asked not to come to school, while others switched to online classes after receiving the threat, he added.