Thousands of protesters rallied in the Bangladesh capital for a second day on Tuesday to demand electoral reforms and the resignation of election officials ahead of January 21 polls.
Authorities tightened security around the election commission office and closed nearby streets to traffic, witnesses said.
Barbed-wire barricades manned by security forces were erected around the downtown office to keep demonstrators away.
The protesters belong to an alliance of 14 political parties that has accused the five election commissioners of bias in favour of former Prime Minister Khaleda Zia.
Zia transferred power to an interim government to oversee the polls after completing her five-year term in office on October 29, but her opponents claim she tried to rig the election by appointing supporters to supposedly nonpartisan positions.
Amid the furor, chief election official MA Aziz last week said he would take three months' leave, a move welcomed by the alliance, although they said it did not go far enough.
They are now focusing their attention on the remaining four commissioners who they accuse of rigging voters' lists, and have threatened to renew a nationwide blockade if the officials are not removed by Saturday.
The demonstrators also want to change the January 21 polls date set by the election commission, saying balloting under the disputed officials will not be free and fair.
Similar protests took place on Monday near the official residence of President Iajuddin Ahmed, head of the interim government.
The election commission said it would go ahead with preparations for the polls, despite the protests.
"We have time constraints. If we don't announce the schedule now, it'll be difficult for us to organize the voting," Abdur Rashid Sarker, secretary of the election commission secretariat, told reporters on Monday.
The interim government, which took over on October 29, has 90 days to hold a vote, according to the Constitution.
The 14-party alliance, led by Zia's archrival, Sheikh Hasina, herself a former prime minister, has threatened to boycott the election unless its demands are met.
Alliance spokesman, Abdul Jalil, accused the election commission of preparing a voters list that "excluded many of our supporters and included fake names so the balloting can be rigged in favor of Khaleda Zia."
Zia's four-party coalition has said it is ready to go to the polls. Clashes between rival political activists have left at least three people dead and dozens injured over the past week.