Witness said BNP standing committee member Mirza Abbas along with his several hundred supporters marched towards their party office around 12:40pm and started staging a showdown there, halting traffic on the road.
Police tried to remove the BNP men from a portion of the road so that vehicles can pass through, but failed to do so.
At one stage, they locked into an altercation with the BNP leaders and activists and started charging batons to maintain the law and order.
BNP leaders and activists also started hurling brickbats at the cops, triggering a fierce clash between the two sides.
A chase-and-counter-chase was going on there till filing of the report around 1:25pm. Police also lobbed teargas to disperse the BNP activists.
At least two police vans were torched and some other vehicles vandalised in the Nayapaltan area.
Huge police took position in front of Bijoynagar Nightingale crossing.
A police official wising anonymity said they may go on further action anytime soon.
He also claimed that some copes were injured in the attack.
BNP leaders and activists also took position again in front of their office while party senior leaders were asking them to exercise restraint and not to respond to any provocation.
BNP assistant office secretary Taipul Islam Tipu told UNB that the clash broke out around 12:5o pm as the police were trying to obstruct their leaders and activists from gathering in front of their office.
Traffic in the areas came to a complete halt following the clash.
Like the past two days, thousands of BNP leaders and activists gathered in front of their office in the morning while many others started joining them in small processions until the clash began as the party continued the sale of its nomination forms for the third consecutive days today among those who want to contest the 11th parliamentary elections with its tickets.
Carrying posters, banners, festoons, placards and portraits of party chairperson Khaleda Zia, acting chairman Tarique Rahman and nomination aspirants, the party activists were celebrating the nomination sale.
On Monday morning, the party formally started the sale of nomination with the purchase of three nomination papers for its jailed chairperson Khaleda Zia. BNP sold 1,326 nomination papers on the first day while 1,896 ones on the second day.
The sale of nomination papers are supposed to continue until November 16.