Nihad El Aabedy and Raheela Mahomed report.
After a week of protests that saw several schools closed, government officials Saturday urged students to end their demonstrations and return to classrooms, the news agency reported.
An official vehicle from the US Embassy in Dhaka, which was transporting Ambassador Marcia Bernicat, was attacked by a group of armed adult men, some on motorcycles, in the Mohammadpur area on Saturday, said the statement.
Alam's organisation, Drik Picture Library, said 30 to 35 men in plainclothes swept into his Dhaka apartment building, saying they were police detectives, and took him into custody.
"We have treated more than 115 injured students so far since the afternoon", emergency ward doctor Abdus Shabbir told AFP, adding some sported injuries consistent with rubber bullets.
The protestors were seen chanting slogans, "We want justice".
The protest began with a small group of students in Dhaka and then spread across the country. "Will we kiss them if they advance towards Awami League office?" general secretary Obaidul Quader said.
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Former first lady Michelle Obama led a slew of celebratory messages to her husband Barack Obama who turned 57 on Saturday. It is a commemorative holiday rather than a state holiday, meaning that schools and government workplaces will stay open.
Giving in to the demands of student protesters, Bangladesh's Cabinet today approved a new road safety law and promised to consider death penalty for deliberately causing accidents as violent clashes between the demonstrators and police continued to cripple normal life here.
The student protesters have demanded tougher punishment for offences involving road accidents.
Witnesses said police fired rubber bullets and tear gas at demonstrators and that alleged pro-government activists attacked youngsters, including some of those rushing to nearby hospitals for treatment.
"It's not true. Nothing happened at Jigatola", Dhaka police spokesman Masudur Rahman told Agence France-Presse (AFP).
A number of journalists were also beaten and had their cameras taken away, reportedly by ruling Awami League party members, according to the report. Many protesters blamed the student wing of the ruling party for the attacks.
The protesters stopped trucks, buses and cars, demanding to see the licenses of drivers and check if vehicles were in roadworthy conditions.
Additional police have been deployed to thwart any untoward incidents and for the security of students, said Iftekhar Alam, spokesperson of Rajshahi Metropolitan Police.
Shipping minister Shajahan Khan, also executive president of Bangladesh Road Transport Workers' Federation, earlier said that buses did not operate on ground of safety and if the situation improved, they would also resume operation.