Image copyright Daily Star Image caption Railway lines across the length and breadth of the country have been vandalised in the course of the disturbances

At least 15 people across Bangladesh have been killed in protests following Monday's government announcement that general elections will be held on 5 January, officials say.

The opposition has rejected the date and called for a transport blockade.

It wants Prime Minister Sheikh Hasina to transfer power to a neutral caretaker government to oversee polls - the practice adopted in previous votes.

The opposition has extended its transport blockade until Friday.

Its supporters have sabotaged railway lines, set fire to buses and taxis, and prevented ferries from sailing. The election commissioner met the heads of the security forces on Thursday to discuss the violence.

The government meanwhile has announced that UN envoy Oscar Fernandez-Taranco will visit Bangladesh on 6 December to hold talks with political parties about ending the election stand-off.

The mass-circulation Daily Star newspaper said that the envoy would carry "a strong message" from the UN chief to rival political leaders to hold "free, fair, credible and inclusive" polls.