
The missing boys were identified as Sabbir Hossain, a ninth-grade student, and his younger brother Sawon Hossain, an eighth-grade student.
They are sons of Helal Hossain of the Mogolhat Tampu Stand area and students of Mogolhat High School.
Police said the two brothers went to the river to bathe with their friend Mehedi at noon.
At one stage, Sabbir and Sawon were swept away by the river's current and disappeared under the water. Mehedi, however, managed to swim to safety.
Locals and members of the Border Guard Bangladesh (BGB) from the Mogolhat camp immediately launched a rescue operation after being informed of the incident.
Later, personnel from the Lalmonirhat Fire Service joined the search operations.
As the boys could not be located, a diving team from Rangpur was called in to assist with the operation, reports UNB.
Rescue efforts were continuing until the filing of this report.
Saad Ahmed, Officer-in-Charge (OC) of Lalmonirhat Sadar Police Station, said police rushed to the spot after receiving the information and were assisting in the ongoing rescue operation.