A global monitoring group says the Islamic State group has claimed responsibility for an explosion targeting a police van in Bangladesh's capital.

Police said Sunday night's explosion in Dhaka's Malibagh area left three people injured, including a police officer, but they were not sure who was behind the blasts.

U.S.-based SITE Intelligence said in a Twitter post that IS was behind it.

Dhaka Police Commissioner Asaduzzman Mia said Monday that the bomb had been planted in the van. He said it was more powerful than an explosion in April in Dhaka that was also claimed by IS.

Two of the injured were being treated in a hospital following Sunday's blast.

Bangladesh has a history of attacks by Islamist radical groups.