As many as 10 people havebeen killed in lightning strikes in three districts of Andhra Pradesh, the State Disaster Management Authority said here on Friday.In a release, the SDMA said seven people were killed in lightning strikes in five mandals of SPS Nellore district, two in Guntur and one in Prakasam district on Thursday.At Chennur village alone under Dagadarthi mandal in SPS Nellore district, three were killed in the incident."We had issued advance warnings with the likely location of the lightning and asked people to stay in safe places. But still the deaths occurred," the SDMA said.For instance, the SDMA sent out bulk text messages and also WhatsApp messages at 10.22 am and 10.58 am alerting people about lightning strikes in Dagadarthi mandal. The strike happened at 12.30 pm and three persons fell victim.Disaster Management Commissioner K Kanna Babu advised people to follow the instructions sent by the department and stay in safe places to avoid such tragedies."Particularly the farmers, farmhands and cattle-grazers should get back to safer places whenever there is a thunderstorm or lightning. This will prevent tragedies," Kanna Babu said.