The attacker could not be identified immediately. Police have cordoned off the area.
The latest incident came a week after a suicide bomber blew himself up at a security forces base near the international airport in the Bangladesh capital, Dhaka, injuring two police officers.
The Muslim-majority country of 160 million people has seen a series of deadly attacks in recent years. In the most serious attack last July, gunmen stormed a Dhaka cafe and killed 22 people, most of them foreigners.
More than 50 suspected militants have been killed and scores arrested since the cafe attack as the government launched a crackdown on Islamists.
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