Talking to UNB, Salahuddin claimed 5-20 activists of Jubo League and Chhatra League equipped with rods and sticks attacked his vehicle on Bamoil Bridge without any provocation around 2pm on his way to his electoral office in Jatrabari after carrying out electioneering.
The BNP candidate said he escaped unhurt, but the vehicle was damaged in the attack.
He claimed that the attackers were supporters of Awami League candidate Kazi Monirul Islam Monu.
Salahuddin protested the incident and demanded immediate arrest of the attackers.
He called upon the Election Commission to take steps for ensuring his security and proper election atmosphere in the constituency.
The by-election to Dhaka-5 seat will be held on October 17, according to the schedule declared by the Election Commission.
The constituency fell vacant following the death of Awami League MP Habibur Rahman Mollah on May 6.