Thousands of demonstrators have gathered in the South African capital Pretoria for protests urging President Jacob Zuma to step down.

Wednesday's march to Union Buildings, the official seat of government, was organised by a coalition of opposition parties following nationwide rallies against Zuma last week.

The president's recent dismissal of Finance Minister Pravin Gordhan stoked public anger over government corruption scandals, record unemployment and slowing economic growth.

The march was led by the leftist Economic Freedom Fighters (EFF) party, along with the Democratic Alliance (DA) and smaller opposition parties.

Al Jazeera's Fahmida Miller, reporting from Pretoria, said the opposition parties show unprecedented unity in coming together for the protests.

"Last week's protests were organised by the civil society and religous groups. But now we have at least seven political parties who have come together and want Zuma to go," she said.

"The message is clear. They want him to go because they say he's bad for the economy and believe these protests could lead to Zuma stepping down."

Gordhan's sacking prompted unprecedented criticism from senior figures in the ruling African National Congress (ANC), including from Cyril Ramaphosa, deputy president.

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The ANC has since tried to close ranks behind Zuma and has pledged to defeat a no-confidence vote in parliament.

The vote is scheduled for next Tuesday but may be delayed due to a legal tussle over whether it should be a secret ballot for lawmakers.

Zuma, who turned 75 on Wednesday, is due to step down as head of the ANC in December, and as president in advance of the 2019 general election.

He is seen as favouring his ex-wife, former African Union chief Nkosazana Dlamini-Zuma, to succeed him.