Bangladesh police on Friday arrested one of the country’s most senior opposition party leaders and banned all public rallies in the capital Dhaka after days of deadly nationwide unrest after student protests that started weeks ago turned violent this week. Dhaka is in the midst of a near-total internet blackout, with phone lines also down.

Police in Bangladesh's capital banned all public rallies on Friday after the deadliest day of ongoing student protests so far saw government buildings torched by demonstrators and the imposition of a nationwide internet blackout.

This week's unrest has killed at least 39 people, including 32 on Thursday, with the toll expected to rise after reports of clashes in nearly half of the country's 64 districts.

Students took to the streets again on Friday morning ahead of pro-government counter-demonstrations slated to begin after midday prayers in the Muslim-majority nation.

Dhaka's police force took the drastic step of banning all public gatherings for the day – a first since protests began – in an effort to forestall another day of violence.

"We've banned all rallies, processions and public gatherings in Dhaka today," police chief Habibur Rahman told AFP, adding the move was necessary to ensure "public safety".

Dhaka Metropolitan Police spokesman Faruk Hossain told AFP that officers had arrested Ruhul Kabir Rizvi Ahmed, the joint secretary of the main opposition Bangladesh Nationalist Party (BNP).

"He faces hundreds of cases," Hossain said, without giving further details on the reasons for Ahmed's detention.

Police in the capital earlier said protesters had torched, vandalised and carried out "destructive activities" on numerous police and government offices.