Political activists seeking the removal of election officials surrounded Bangladesh's main administrative secretariat in Dhaka on Wednesday, as a UN envoy flew in to assess the situation ahead of elections in January.
Witnesses said activists of a multi-party alliance led by Sheikh Hasina, chief of the Awami League, choked streets leading to the secretariat, preventing officials from going in or out.
"It's a total gherao (siege) of the secretariat," one witness said, adding that authorities deployed hundreds of riot police to try to prevent violence.
Violence has swept the impoverished South Asian country in the run up to the election set for January 21.
Craig Jenness, director of the UN Electoral Assistance Division, arrived in Dhaka today for a three-day visit to assess the situation before the poll and then prepare a report for Secretary-General Kofi Annan.
Officials said Jenness would meet President Iajuddin Ahmed, who also heads a caretaker administration in change of holding the election, former prime minister Begum Khaleda Zia, Sheikh Hasina, foreign secretary M Hemayetuddin and civil society leaders.
Annan has appealed to Bangladeshi leaders to work together to ensure free and fair elections.
Nut political analysts say past experience showed such efforts usually fail in Bangladesh.
A similar mission in 1994 by the then Commonwealth secretary-general to resolve differences between political rivals ended in a fiasco.
Animosity between Khaleda and Hasina has intensified so much that the two women have not spoken to each other for about a decade.
At least 40 people have been killed and hundreds injured in clashes between political rivals since late October, when Khaleda ended her five-year term as prime minister and handed power to the interim government.
The violent campaign forced Chief Election Commissioner MA Aziz to take three months' leave, leaving one of his deputies, Mahfuzur Rahman, in charge.
The 14-party alliance led by Hasina wants to remove all key officials at the commission to ensure free and fair voting.
Hasina and her allies accuse the commissioners of being biased towards Khaleda's Bangladesh Nationalist Party (BNP) and its ally the Jamaat-e-Islami party.
The alliance has enforced two crippling countrywide transport blockades in the past two weeks, closing everything from schools to ports.
Another shutdown looms as Hasina has asked the president to step down as head of the interim government by Saturday, accusing him of failing to prove his neutrality.