Schools, shops and businesses were closed across Bangladesh and roads and highways were deserted as the Bangladesh Nationalist Party (BNP) and 17 allies enforced the day-long protest, their sixth in the past four weeks.

Two small bombs exploded and protesters damaged vehicles in the Bangladeshi capital Dhaka Thursday, during a nationwide strike and demonstration against the jailing of 33 opposition leaders, police said.

The opposition anger was sparked by a Dhaka court decision on Wednesday to deny bail to 33 key figures, including ex-ministers and lawmakers, over charges stemming from an arson attack during an anti-government protest last month.

The BNP has slammed the charges as baseless and fabricated, with party spokesman Nazrul Islam Khan saying they were "awestruck" by the court's decision.

Security has been tight across the country with 10,000 policemen patrolling the streets of Dhaka, city police spokesman Masud Ahmed told AFP, adding at least 15 people including a senior BNP official had been arrested.

"Protesters also damaged vehicles this morning and torched four buses and a taxicab Wednesday," he said.

Two small bombs exploded outside a German technical school in Mirpur, Dhaka's northwestern suburb, but no one was injured, local police chief Kazi Wajed Ali told AFP.

On Wednesday scores of people were injured as police fired rubber bullets at hundreds of oppositionprotesters who rioted in the northwestern town of Thakurgaon, home to the BNP's second-highest official who was also denied bail.

Bangladesh's often turbulent politics have returned to near boiling point over the disappearance of a top regional figure from the BNP, Ilias Ali, on April 17.

The BNP fears Ali has been killed and accuses the elite Rapid Action Battalion security force of abducting him on government orders -- an allegation that has been strongly denied by security forces and the government.

Ali is the highest-profile opposition politician to have "disappeared" since Prime Minister Sheikh Hasina took power in January 2009. AFP