Update - 12.38pm: South Africa's President Jacob Zuma has said the ruling party, the ANC, has not given clear reasons for him to resign and called his treatment "unfair".
Mr Zuma broke his silence today in a live interview with state broadcaster SABC as the nation awaited word on whether he would obey a ruling party order to leave office.
Earlier in the day police had raided the home of a business family linked to the embattled leader.
Mr Zuma says the ruling African National Congress has not followed party procedures in trying to unseat him. The ANC wants parliament to vote on Thursday on a motion of no confidence if he does not resign today.
"I need to be furnished on what I've done," Mr Zuma says. "What is this hurry?"
Agents from the Hawks, an elite police investigative unit, earlier entered the compound of the Gupta family in an affluent neighbourhood of Johannesburg. Three people were arrested in operations at various addresses, the South African Broadcasting Corporation reported.
The family is suspected of using its connections to the president to influence Cabinet appointments and win state contracts, and has been a flashpoint for national anger over corruption in state enterprises during Mr Zuma's tenure. Both the Guptas and Mr Zuma say they have done nothing wrong.
A judicial commission is preparing to investigate the alleged corruption associated with the India-born Gupta brothers, who moved to South Africa around the time of the transition from white minority rule to democracy in the 1990s. One of Mr Zuma's sons, Duduzane, had a business relationship with the Guptas.
Deputy President Cyril Ramaphosa is poised to replace Mr Zuma, who could face a motion of no confidence in parliament if he defies his party's order to step down.
Mr Zuma's second five-year term ends with elections in 2019, but the ANC wants to remove him so that it has more time to recover the confidence of disaffected voters and hopes to pass a motion of no confidence on Thursday unless the president agrees to their demand first.
As the Gupta-linked investigation proceeds, Mr Zuma could face corruption charges tied to an arms deal two decades ago.
South Africa's chief prosecutor is expected to make a decision on whether to prosecute Mr Zuma on the old charges, which were reinstated last year after being thrown out in 2009.
In another scandal, South Africa's top court ruled in 2016 that Mr Zuma violated the constitution following an investigation of multimillion-dollar upgrades to his private home using state funds. The president paid back some of the money.
10.55am: Jacob Zuma faces no-confidence motion after police raid Gupta family compoundSouth Africa's ruling party is preparing for a no-confidence motion against President Jacob Zuma tomorrow.
Paul Mashatile, a senior official in the African National Congress, says the aim of the vote is to remove Mr Zuma so that Deputy President Cyril Ramaphosa can take over.
Mr Mashatile said Mr Zuma faces a deadline today to respond to a ruling party order to leave office.
"We can no longer keep South Africa waiting," Mr Mashatile says.
Mr Zuma has been discredited by corruption scandals. Police have raided the home of a prominent business family with links to the president.
South African police target business family linked to Zuma
South African police have raided the residential compound of a business family suspected of using its ties to President Jacob Zuma to influence Cabinet appointments and land state contracts.
Agents from the Hawks, an elite police investigative unit, entered the compound of the Gupta family in Saxonwold, an affluent neighbourhood in Johannesburg, on Wednesday.
The raid happened as the ruling African National Congress Party awaited a response from Mr Zuma after instructing him on Tuesday to quit office because of a series of scandals.
The Gupta business family has been a flashpoint for national anger over corruption in state enterprises during Mr Zuma's tenure. A judicial commission is preparing to investigate the allegations.
Mr Zuma and the Guptas deny wrongdoing.