Eyewitnesses said a few pickets fought a pitched battle with the police after they damaged vehicles and set things on fire on the street near Education Building and Food Building, close to the Bangladesh Secretariat, around 3pm on Tuesday.
The police, however, said the BNP activists gathered during party chief Khaleda Zia's court appearance took part in the attack on them and vandalism.
But, the BNP claimed the police launched an unprovoked attack on their leaders and activists.
The BNP leaders and activists gathered in the court area on Nazimuddin Road on Tuesday as Khaleda made a court appearance for the recording of the witnesses' statements in Zia Orphanage Trust case.
"I was waiting in the area as sir (Fazlur Rahman) went to meet the finance minister," Salam said.
The diver of the deputy secretary to the Power Development Board gave bdnews24.com a similar account of the incident.
"I immediately left the areas as soon as the pickets started vandalising vehicles," Md Shajahan said.
Shahabagh Police Station Inspector (investigation) Md Zafar Ali told benews24.com the activists of BNP, while coming back after Khaleda's court appearance, damaged vehicles on the street and threw stones at police.
He said the protection vehicle of the judge in BDR mutiny case, Nazrul Islam, also came under attack.
BNP Senior Joint Secretary General Ruhul Kabir Rizvi said, "The BNP leaders and activists lined up along the streets to wave their party chief on her way back from the court but the police attacked them unprovoked."
"Police lobbed teargas shells, resorted to baton charge and arrested our leaders and activists," he said adding "this is nothing but a manifestation of the autocratic mentality of the government."
The ruling Awami League leaders often say the BNP is out to create a situation in the country over Khaleda Zia's graft case.