Security was tight in Bangladesh capital Dhaka on Monday as tens and thousands of opposition supporters prepared to rally near the presidential palace to demand a delay of next month's elections.
The Opposition said they expected tens and thousands of activists to join the "grand rally" where Sheilkh Hasina, leader of the main opposition Awami League, will make a "key speech" on the upcoming polls.
"She will demand a reconstitution of the election commission and a delay in election schedule by more than a month," Obaidul Kader, an opposition spokesman said.
"It is now impossible to join January 23 elections because the caretaker government has yet to implement some of our key electoral demands which are must for free and fair polls," he said.
The latest demand comes amid a worsening political crisis in the impoverished South Asian nation, where opposition protests have brought the country to a standstill and the army has been called out to restore order.
The opposition has also been demanding that President Iajuddin Ahmed, the head of the interim government, remove two controversial election commissioners seen as being biased in favour of the outgoing Bangladesh National Party (BNP) of Khaleda Zia.
The president has said he will send one of them on extended leave but has so far refused to do the same for the other.
The opposition also wants Ahmed, who heads the interim government tasked with organising free and fair polls, to step down -- a demand the president has squarely rejected.
Pre-poll political violence has already claimed at least 34 lives and injured thousands, and has cost the country heavily in financial terms.
Experts said the demand to delay elections will create a constitutional crisis as the country's interim government has the mandate to organise elections within only 90 days of its tenure.
The mandate of the interim government ends on January 27 but the opposition is now demanding that the elections be held late February or in early March.
The BNP and its Islamist allies have opposed any delay in elections.
Bangladesh's interim government vowed last week it was making a last-ditch attempt to meet opposition's remaining demands within three days and ensure polls can go ahead on schedule. But the deadline passed on Saturday.
"We are still hopeful of finding a solution within this week," interim cabinet member Shafiqul Haq Chowdhury told reporters.
Security has been tightened in and around the Paltan Maidan, the rally venue. At least 7,000 policemen were deployed near the site to prevent violence, police inspector Mahbubur Rashid said.
The elite Rapid Action Battalion forces have scoured the venue with sniffer dogs and security equipment. All the roads around the presidential palace have also been blocked, police said.
The armed forces were called out by the president a week ago and have fanned out across the country, sparking the resignations of four cabinet members, who said the move "violated the democratic process".