South Africa's ruling African National Congress (ANC) has said it plans to sue opposition politician Julius Malema after he threatened to remove President Jacob Zuma's government through the "barrel of a gun".

Monday's development came a day after Malema told Al Jazeera that the ANC used violence to suppress dissent, citing an incident last year when members of his Economic Freedom Fighters (EFF) party were ejected from parliament after heckling Zuma.

"We will run out of patience very soon and we will remove this government through the barrel of a gun," Malema, Zuma's one-time protege and a former ANC youth leader, said on Talk to Al Jazeera.

"Part of the revolutionary duty is to fight and we are not ashamed if the need arises for us to take up arms and fight."

EFF protest marches were often met with violent resistance by security forces, he said.

In response to the comments, the ANC said it would pursue legal action against him.

"These remarks are a call to violence, are inflammatory, treasonable and seditious and should be treated with extreme seriousness," the ANC said in a statement.

"The ANC calls on state authorities to urgently investigate this matter and act against such conduct."

Al Jazeera's Tania Page, reporting from Johannesburg, said: "The EFF don't have any military hardware and are not capable of carrying out the threat to remove the government over a barrel of a gun."

Despite that, she said, the party was a potent political threat to the ANC.

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"Within a year of forming the EFF, Malema won 6 percent of the votes in the last general election," she said.

"They [the government] are worried about his appeal to young voters and the appeal to the discontented within the society."

South Africa will hold local government elections on August 3.

The EFF and the main opposition party, the Democratic Alliance, are expected to make inroads into majorities held by the ANC in large metropolitan areas, including the capital, Pretoria.

Malema has accused the ANC of failing to address inequality between blacks and whites since Nelson Mandela swept to power on a wave of optimism at the end of apartheid in 1994.