The deceased were identified as Rajib, 24, son of Abdul Mannan, and Moktadir Mia, 60, son of Kalu Mia, both hailing from Charigram village in Mithamoin upazila in Kishoreganj; Mabia Begum, 39, wife of Saifuddin, resident of Kornakhali Mirzapur village of Shibganj upazila of Chapainawabganj.
Police could not confirm the identity of another victim.
In Kishoreganj, Rajib and Moktadir were killed in a head-on collision between a tractor and an auto rickshaw on Kishoreganj-Karimganj road in Shatal area of the district town around 2:30pm, said Abu Bakar Siddique, officer-in-charge of Kishoreganj Sadar Model Police Station.
The driver and a passenger of the auto rickshaw also sustain severe injuries, he added.
In Chapainawabganj, pillion rider Mabia was killed after being hit by a speeding truck on Chapainawabganj-Sonamansjid Road in Shibganj Upazila.
“Mabia fell down and died on the spot after a Sonamasjid-bound truck hit the motorcycle around 9am,” said sub-inspector Faruk Khan of Shibganj Police Station.
In Sirajganj, an unidentified youth, believed to be around 20-year-old, was killed after being hit by a truck on Sirajganj-Nalkha Highway in Shialkhola area in Sadar Upazila around 12:45pm.