Two homemade bombs exploded Monday on the popular Indian Ocean tourist island of Zanzibar, but with no casualties, police said, in the latest in a series of attacks.

"Investigations are ongoing to find out details of the blasts and the motive behind them," assistant police commissioner Mkadam Khamis told reporters.

At least 163 people died when a ferry capsized off the popular tourist archipelago of Zanzibar, but over 100 people are still missing, a minister said Saturday.

"We have recovered 163 people who have died and we have rescued 325 survivors," said Mohammed Aboud, Zanzibar's state minister for emergencies, dramatically updating an earlier death toll of 53.