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Police used batons to disperse stone-throwing opposition supporters outside a court in Bangladesh's capital Wednesday after a judge denied bail to 33 senior opposition members charged with involvement in an arson attack during an anti-government strike last month, witnesses said.

The opposition announced a daylong general strike across the country Thursday in response to the ruling.

The defendants include former Cabinet ministers and the acting secretary general of the Bangladesh Nationalist Party led by former Prime Minister Khaleda Zia. The party heads the 18-party opposition alliance that has called a series of general strikes to protest alleged government involvement in a politician's disappearance.

The opposition also set a June 10 ultimatum for the government to restore a caretaker government system to oversee the next national elections, due in 2014. The government of Prime Minister Sheikh Hasina scrapped the 15-year-old system last year in what the opposition says was part of a plan to rig the elections.

The opposition has said it will boycott the elections if the system is not restored.

Political tensions have sharply escalated since Elias Ali, an organizing secretary in Zia's party, went missing along with his driver on April 17 from a street in Dhaka.

The opposition says the government and its security agencies are behind his disappearance. Authorities deny the allegation.

As a result of Wednesday's ruling, the 33 defendants will remain in jail until further legal proceedings.

The opposition says the arson charge involving a bus burning on April 29 is politically motivated.

Opposition supporters protested the ruling outside the court, and police charged at them with batons, said Kamruzzaman, a lawyer at the scene who uses one name. Several people were injured, he said.

ATN Bangla television station said several opposition supporters were arrested. Other stations said at least two vehicles were burned in separate incidents in Dhaka immediately after the ruling. Opposition activists also smashed vehicles in protests in several other towns, news reports said.

Defense lawyers argued Wednesday that the defendants should be granted bail because the charges were bailable, but prosecutors said they would disturb the peace if they were released.

A local rights group, Ain-o-Salish Kendra, says at least 22 people, mostly politicians, disappeared in the first three months of this year. Another group, Odhikar, says more than 50 have disappeared since 2010.

During a visit to Bangladesh earlier this month, U.S. Secretary of State Hillary Rodham Clinton raised Ali's disappearance with the government, reflecting international concern over the issue.

Amnesty International and New York-based Human Rights Watch have also expressed concern and urged the government to investigate.