DHAKA: Bangladesh Prime Minister Sheikh Hasina plans to speak by telephone to opposition leader Khaleda Zia later on Saturday to try to defuse a growing crisis over forthcoming elections, an aide to the premier said.

Bangladesh's politics have been held hostage for two decades by bitter rivalry between Hasina and Zia, who has served twice as premier, and the “battling begums” very rarely talk to one another.

Observers say it is believed to be at least a decade since the two women have spoken.

“Both the leaders will talk” by telephone, Hasina's aide Mahbubul Haque Shakil told AFP. Zia's spokesman, Maruf Kamal Khan, confirmed the planned conversation.

Tensions rose in Bangladesh on Friday after supporters of Zia's Bangladesh Nationalist Party (BNP) and its Islamist allies clashed with the ruling party and police in cities and towns across the nation, leaving at least seven people dead and hundreds injured.

Paramilitaries and police fired at thousands of rampaging opposition supporters after they hit the streets, defying a government ban on rallies.

Police said opposition supporters attacked them with small bombs, firearms and sticks, prompting them to open fire.

Zia addressed a huge rally of over 100,000 opposition supporters in Dhaka on Friday, renewing her demand that Hasina quit and make way for a caretaker government to take over to supervise the elections due in January.

Zia announced a three-day nationwide opposition-led shutdown, starting Sunday, if Hasina did not agree to talks.

Zia's spokesman said the two leaders would discuss Zia's demand for holding the parliamentary elections under a neutral technocrat-led government.

“She (Khaleda Zia) is eager to talk. The whole nation wants them to talk to end this stalemate over the elections,” Khan told AFP.

Zia branded the government “illegal” as of Friday, citing a legal provision that required a neutral caretaker government to be set up three months before elections.

But the ruling Awami League abolished the provision in 2011, handing the job of overseeing polls to an overhauled Election Commission.

Hasina argues the caretaker administration system enables the army to seize power in a country which has seen at least 19 coups since 1975.

Hasina has rejected Zia's demand for her to step down, calling it unconstitutional.

Last week, Hasina instead floated a proposal to set up an all-party interim government which would include cabinet members from Zia's BNP, while she would remain head of the government.

The nation has a long history of political violence, but this year has been the deadliest since Bangladesh gained independence in 1971.

At least 150 people have been killed since January after a controversial court began handing down death sentences to Islamist leaders allied to ex-premier Zia.

An ex-mayor of Dhaka fuelled tensions last week after he asked opposition supporters to join the protests armed with machetes and axes.

Fearing clashes, police banned all political rallies and street protests in major cities. But on Thursday night they decided to allow the BNP to hold the Friday rallies after the party vowed to defy the ban.

The last time the two main parties fought street battles was in late 2006, when dozens were killed, causing the country to shut down for weeks before the army stepped in to cancel elections and set up a military-backed caretaker government.

The BNP has vowed to boycott polls without a caretaker government, insisting the system has delivered four successive free and fair polls since 1990 when democracy was restored after over a decade of military rule.