His remarks came on Saturday at a media briefing, when the party announced countrywide agitations for Sunday after being denied permission for a rally in Dhaka.
The party observes Jan 5 as the 'Death of Democracy Day' marking the 2014 parliamentary elections that it boycotted.
It announced programmes for two days this year to observe the day.
Black-flag marches were held across the country, except Dhaka, on Thursday.
Senior Joint Secretary General Rizvi said BNP supporters in many places were obstructed by police and ruling Awami League activists during the protests.
The Dhaka rally for Saturday was all about observing the 'Death of Democracy Day'. Government denied permission for it.
"More than 50 BNP activists, including females have been critically injured on Thursday when ruling party supporters attacked the procession in Barisal city," Rizvi said at the press conference.
He claimed that the government seems determined to wipe out the opposition.
"And that's why criminals are being patronized. The Awami League has become a breeding ground of criminals," said Rizvi.