Manzurul Imam and Mozammel Haque, two Awami League politicians, were gunned down in southern Khulna and Dhaka by unidentified gunmen.
The killings sparked widespread protests around the country.
The Dhaka strike is likely to disrupt operations at the country's main Chittagong port, and trading on the stock exchange has been suspended.
Authorities have deployed hundreds of extra police and kept paramilitary troops on standby to prevent violence.
Awami chief Sheikh Hasina accused the ruling Bangladesh Nationalist Party (BNP) of killing political rivals to consolidate power.
"They are slaying our leaders and workers to stay on the saddle for a longer period, which they do not deserve anymore," she told a rally in Dhaka on Wednesday.
However, the BNP has rejected the charges.