The protest was one of the largest in Dhaka in recent months Enlarge Image

Security was tight, with thousands of police on the streets.

An alliance of 14 opposition parties called the protests to demand the resignation of election commissioners.

They are accused of favouring the government, and the opposition have threatened to boycott the elections which are due in January.

'Rig polls'

The opposition have been staging a series of general strikes and street protests in recent months, with many turning violent with clashes between opposition supporters and police.

The protesters say they may boycott the elections

Under Bangladesh's constitution, the Prime Minister, Khaleda Zia, is to hand over power to a caretaker administration when her five-year term expires in October.

The BBC's Roland Buerk in Dhaka says that opposition supporters marched to the rally in groups chanting slogans, surging past the thousands of police officers on duty in the city.

The Awami League and its 13 allies allege that the government is preparing to rig the polls due in January.

They want the election commissioner and his deputies to be removed, and they want a say in who will lead the caretaker government - an interim administration that will take over in late October and oversee the polls.

The opposition have already called a general strike and a blockade of major roads and railways later this week, and are threatening to boycott the elections altogether.

'Non-stop action'

The prime minister has rejected the opposition's demands, saying the Awami League and its allies are trying to disrupt the process because they fear losing.

Correspondents say Bangladesh is entering turbulent times

But opposition leader Sheikh Hasina said that electoral reforms are vital to make the next election free, fair and acceptable to all parties.

According to the Bangladeshi constitution, a non-party caretaker administration will assume power after the five-year tenure of the prime minister expires next month.

The former Chief Justice of the Supreme Court, KM Hasan, is due to take over as the head of the caretaker administration.

But the opposition parties say he was a member of the ruling Bangladesh Nationalist Party before he was appointed a judge and that they will not accept him.

Sheikh Hasina told the rally that the opposition alliance will call for "non-stop action" if Mr Hasan takes over power.