In Sylhet, a man and his son were killed while harvesting paddy at Kalaruka area of Sylhet Sadar upazila at noon.
They were identified as Shomsher Ali, 58, and his son Saiful, 12, of the area.
Jedan Al Musa, additional commissioner of Sylhet Metropolitan Police, said the lightning struck Shomsher and his son around 12:30pm when they were harvesting paddy in Kalaruka haor area, killing them on the spot.
Ten other men were injured in another incident of lightning at Companiganj upazila, he added.
Meanwhile, a teenage boy – Rahi AHmed, 16, son of Ansar Ali of Khaiddar village –died after being struck by a lightning strike in Osmaninagar Upazila around 11am.
He was harvesting paddy, said Osmaninagar Police Station Officer-in-Charge Rashed Mubarak.
In Sunamganj, four farmers were killed in separate incidents of lightning strikes in four upazilas in the morning.
In Shalla upazila, Shankar Sarker, 28, son of Surendra Sarker of Narayanpur village in Habibpur union, was struck by lightning at Bandarbil haor.
Locals said the lightning struck Shankar when he was returning home amid storm around 11am, leaving him critically injured. Later, he was taken to upazila hospital where doctors pronounced him dead.
In Dirai upazila, Taposh Mia, 30, hailing from Joluska village in Azmiriganj upazila of Habiganj, was killed while he was harvesting paddy at Chayar haor.
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In Jagannathpur upazila, Md Shipon Miah, son of late Tobarok Ullah, resident of Baudhoron village in Holdipur union, died in lightning strike in Noluar haor.
Farid Miah, 35, son of Amirul Islam, resident of Uttar Gazinagar village, died along with two of his cattle after being struck by a thunderbolt at Gazinagar haor of Dakhshin Sunamganj upazila in the morning.
Md Mizanur Rahman, superintendent of Sunamganj police confirmed the incidents.
Lightning strikes claim hundreds of lives in Bangladesh every year. The deaths mostly occur in a warmer period from March to July.