Traders are also being told by the president "there is no excuse" to hike their food prices.

Sugar shortages mean prices have rocketed over the past three months in Tanzania and in its semi-autonomous islands of Zanzibar.

Their governments say low production is to blame.

While visiting markets on Monday, Zanzibar’s President Hussein Ali Mwinyi said the government was tackling inflation but that some dishonest traders still kept prices artificially high - including for locally produced cassava, fish, vegetables and fruits.

"Stop unnecessary price hikes during Ramadan, causing inconvenience to most of the poor," he said.

Zanzibar has a Muslim-majority population. The month of Ramadan, when Muslims fast from dawn to sunset, is due to begin in less than two weeks.