Using the acronym by which the president is known, prominent opposition leader Choguel Maiga told a news conference that “the only watchword remains the resignation of IBK”.
He said a “second phase of civil disobedience” would occur three days after the Muslim festival of Eid al-Adha, which the faithful will celebrate this week.
Mahmoud Dicko, a Saudi-trained imam who is considered the figurehead of the opposition June 5 Movement, also told reporters that he had asked Prime Minister Boubou Cisse to step down.
The announcements mark an entrenchment for the movement, which has not budged from urging Keita’s resignation despite several high-profile efforts to mediate the political impasse.
The loose alliance of opposition groups and religious leaders has since last month has been channelling deep anger in Mali over a dire economy, perceived corruption and a brutal jihadist conflict.
The disparate alliance of opposition groups and religious leaders had already on Tuesday dismissed a plan to break the impasse with Keita, which the 15-nation regional bloc ECOWAS had put forward the previous day.
West African leaders had suggested forming a new unity government to resolve an election dispute that has sparked outrage.
By Monday evening, Keita had already appointed a stripped-down government with the intention to recruit opposition members.
Cisse also visited Dicko on Tuesday evening to invite him to bring his June 5 Movement into a unity government, at which point the imam asked him to step down.
“Mali is not a submissive or resigned people,” Dicko said on Wednesday. “The Malian nation must be restored by Malians for Malians and for Malians.”
‘Not going to resign
Keita, in power since 2013, has come under increasing pressure to resolve Mali’s brutal eight-year-old jihadist revolt, and kickstart the slumping economy.
But much of the Sahel nation’s current tension was sparked in April, when the Constitutional Court tossed out 30 results from long-delayed parliamentary elections — a move that benefited Keita’s party.
Protests ratcheted up into a crisis on July 10 when an anti-Keita rally organised by the June 5 Movement turned violent.
Eleven people died in clashes with security forces over several days, marking the bloodiest political unrest the former French colony has seen in years.
But the June 5 Movement has continued to insist on Keita’s departure, despite two ECOWAS mediation missions which suggested a new unity government, and a resolution to the election quarrel.
ECOWAS leaders confirmed that plan via video link on Monday — sticking by Keita — and backed a new vote for the 30 disputed seats in the election.
But 29 of the 30 MPs whose election victories are in question refused to step down on Wednesday.
“We’ve come together and we’re not going to resign. Our constitution is being violated by the ECOWAS declaration,” opposition MP Gougnon Coulibaly told reporters.
Wednesday’s rejection marks at least the fourth time that Mali’s opposition has rebuffed efforts at compromise, raising the spectre of further unrest.
The standoff with Keita has alarmed Mali’s international allies and neighbours, who are keen to avoid the country sliding into chaos.
Far from the capital, much of the vast West African state lies outside government control and is overrun by jihadists and ethnic militias.
Mali has been struggling to quell a Islamist revolt that first emerged in the country in 2012, then spread to the centre, and to neighbouring Burkina Faso and Niger.
Thousands of civilians and soldiers have died in the conflict to date, and hundreds of thousands have had to flee their homes.